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How to Delete or Disable Active Fuel Management (AFM) on GM Engines

LS Corvette engine - What is Active Fuel Management (AFM)?

(Image/Lethal Garage)

Active Fuel Management (AFM) is a trademarked General Motors technology that improves gas mileage by shutting down half of the cylinders under light-load conditions to reduce fuel consumption. It is also known as Displacement on Demand (DoD) or cylinder deactivation.

How Does AFM Affect Performance?

AFM is good for gas mileage and can be 5-7 percent more fuel-efficient under certain conditions.

So Why Turn it Off?

There are a few reasons:

  1. Many people find the four-cylinder sound annoying if their vehicle is equipped with a louder aftermarket exhaust.
  2. Some drivers want V8 power under their foot at all times.
  3. AFM lifters have a history of failing and oil consumption can be a problem.

How to Delete or Disable AFM on GM/Chevy Engines

There are two ways to disable or delete Active Fuel Management on your GM or Chevy Gen IV LS or LS-based Vortec engine—one is to install an AFM Disabler, and the second is to install an AFM Delete Kit. Here’s what you need to know:

1. Install an AFM Delete Kit

An AFM Delete Kit is recommended when an AFM lifter fails or when doing performance upgrades. It replaces the AFM components with standard parts.

When installing an AFM delete kit:

  • You MUST upgrade to a non-AFM camshaft because the cam lobes in the four AFM cylinders are ground differently. The engine will have 25 less pounds of compression in those four cylinders which can result in a misfire code.
  • You will need to turn off the AFM system using a computer programmer or custom tuning.
  • It’s a little more work, but it’s recommended that you plug the pressure relief valve in the oil pan.
  • It is also recommended that you switch to a standard-volume oil pump.

2. Install an AFM Disabler

An AFM Disabler is an electronic device that plugs into the OBD-II port, under the dashboard. It prevents the computer from switching over to four-cylinder mode. It’s a simple and effective way to turn off the AFM system and provides the added bonus of improving exhaust sound.

NOTE: A disabler device should ONLY be used if the valvetrain is in good working order.

Engines with AFM use a high-volume oil pump. When you eliminate the AFM system, the extra oil is no longer needed. Excess oil will be pushed out of the pressure relief valve into the oil pan. This will spray oil on the bottom of the cylinder walls which can cause oil burning, especially in high-rpm engines.

Which Option is Best—a Disabler or Delete Kit?

As long as a lifter hasn’t started to fail, you can get by with a less-expensive disabler as preventative maintenance. If a lifter has already started to fail, an AFM delete kit and non-AFM components are the way to go.

NOTE: If you were in a situation where you’ve installed the AFM delete kit, but don’t have access to a programmera disabler can still be a viable option. To do this, you need to leave the AFM solenoid pack connected to ensure no codes are thrown. You can reuse the original valley cover OR use a non-AFM valley cover, leave the harness connected, and tuck the solenoid pack away.

GM/Chevy Engines Factory-Equipped with AFM

Engine DisplacementRPO Code
5.3LLY5LC9LH6LMGLS4
6.0LL76L77LFALZ1
6.2LL94L99

How to Identify AFM Engine Components

The AFM system can be identified by its components. Look for the following:

1. Valley Cover

The AFM cover is called the Lifter Oil Manifold Assembly (LOMA). It’s ribbed with solenoids on the underside. It also has an electrical connector on the back. (Non-AFM engines have a smooth cover.)

LS - Lifter Oil Manifold Assembly (LOMA)

2. Engine Block

All Gen IV engine blocks have AFM towers and oil passages cast in. However, they are only functional on engines that used AFM.

LS - AFM Towers

3. Lifters

AFM engines use special lifters for cylinders 1, 4, 6, and 7. They are taller and have special oil holes.

LS - AFM lifters labeled

Engines with AFM also use a special camshaft, a high-volume oil pump, and a pressure relief valve in the oil pan.

3. Oil Pressure Relief Valve

This valve is located on the oil pan rail and prevents excessive oil pressure from negatively impacting the AFM components. The original version sprayed oil on the cylinder walls and increased oil consumption. In 2010, GM added a deflector (p/n) NAL-12639759 to redirect in into the pan. This should be added to your earlier model if you experience oil consumption.

The valve itself is part number W0133-2574213. If you want to delete it entirely, it’s a M14 x 1.5 pipe plug or you could use the Improved Racing plug p/n IRP-814-M14-Kit.

How Active Fuel Management (AFM) Works

How Active Fuel Management (AFM) Works

(Image/GM Media)

When engine load is low:

  1. The computer sends a signal to the LOMA.
  2. The LOMA solenoids open.
  3. Oil flows to the special lifters through the AFM towers.
  4. The oil collapses the plunger inside the lifter.
  5. The collapsed lifters will not engage the pushrods and both valves remain closed.

Since no air can get in or out, four cylinders provide no power. The engine is running on only four cylinders.

The AFM cylinders are opposite of one another in the firing order. In four-cylinder mode, they act like air springs and allow for smooth operation.

As engine load increases:

  1. The computer sends a signal to the LOMA.
  2. The LOMA solenoids close.
  3. Oil bleeds off the lifters.
  4. The lifters return to normal operation.

All eight cylinders are now powering the engine.

NOTE: Some parts are not legal for use in California or other states with similar laws/regulations.

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164 Comments

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  3. What if the pressure relief valve is stuck “OPEN” and the oil pressure never gets up to where it needs to be? I’ve got about 6 to 8 psi of oil pressure after the engine gets warm and I have to stop at a traffic light. NOT GOOD!!

  4. Is the Pressure relief valve replaceable? Does the Pressure relief vavle ever go bad??

  5. GM tried this on cadillacs about 20 years ago and if memory serves me correctly it was a disaster

    • Trevin Martin says:

      368 CADI

      • 1981 Cadillac V 864. I sold them when they were new. They lasted one year with big problems. GM switched over to the 4100 v-8 in 1982.

    • I had privilege to work on some of that garbage they never did work . Anyway that horrible experiment was in the late 70’s early 80’s along with those converted Diesel engines…..those like the 8-6-4 nonsense were just terrible failures. All I can say is they now try this again and they are still having trouble…..when will they ever leave well enough alone

      • It’s not GM’s choice to use AFM. They are being forced by the feds to use stuff like AFM to meet the CAFE requirements. Just like Ram and their trash MDS system or Ford and their throwaway Ecobust engines.

    • Mark Wetzel says:

      Remembered that after I bought my Tahoe. Now I’m here tring to figure out what to do.

      • Ditto , never buy a throw away vehicle again is my recommendation and my fix . The wife however found this ‘deal ‘ on an Envoy Denali . .That was a year ago and now I have a collapsed lifter and the most inexpensive repair $2200.00 for a partial lifter replacement. Looking for another Toyota at this point to match my 1985 4 runner with 380.000 miles and no issues since new. Oh,the ‘throw away’ vehicle has 77,000 miles and has always had meticulous maintenance . Junk . I remember those Other GM vehicles that the consumer tested for GM and paid GM for the honor. On the caddis it helped to relocate the computer inboard the passenger compartment to keep them cool helped . Now it appears GM and their handlers want to push the ‘electric market ‘ with throw away junk that is mechanically weak . Now I know why there wa such a push to get ‘ older ,less efficient’ vehicles off the roads. Welcome to socialism folks . . . .IMHO .

  6. I got as high as 23mpg on the highway in my ’89 K1500 with 350ci and a five speed manual. How about if they just let us have a manual transmission agains for fuel mileage?

    • jack hanson says:

      Double digit MPGs in my 98 K1500 would be a dream lmao. i currently get 8 mpg with the vortec 350 and a 4l60…

    • Victor Barreiro says:

      They should let us the better mileage. If someone didn’t want to spend gas buy a Toyota.

      • Robert Thomas says:

        I know a few guys with Tundras. They don’t so any better than domestics on mpgs…

      • Thomas Davis says:

        I had a 2005 Sequoia V8 only got 12 mpg

      • I may just do that Vic. I have 4 GMC’s in my driveway right now only one with AFM it’s always popping DTC’s, ’06 Yukon (not AFM)never had a light in 12 years! GM get a clue! Did Obama make them do this?

      • Toyota’s 5.7 is one of the biggest gas guzzlers among half-ton trucks. Plus the 5.7 has its own problems with VVT reliability and the rest of the truck is flimsy junk.

      • I have a 2012 Chevy Avalanche. Thanks to a properly maintained 5.3 with AFM, I can routinely get over 20 MPG on the highway. No other V-8 truck of similar weight can do that (except another GM with AFM). This is my second Avalanche and I never had any issues with either of them.

        • My Chevy truck with fuel management can not touch my 2000 Chevy with out fuel management. The older truck gets 19 mpg the newer truck with fuel management gets 14.

        • James Fisher says:

          No other truck my ass .lol my 99 silverado 1500 with the junk LR4 4.8l and 320k miles 9n itgets 21mpg all day long with 93 octane gas in it

  7. I have a ’08 6.0L out of a Silverado with an aftermarket oil pan that has no provision for a pressure relief valve. What can I expect with the AFM in place, or, with AFM disabled (not deleted)?

    • andy miller says:

      Disable the afm. Install ls3 valley cover. It has the orings in place, that seals the towers. The pressure relief in the pan opens at around 45psi to prevent over pressurization of the vlom solenoids. They have plastic casing, so you can imagine what will happen with aged plastic.

    • 6.0 doesn’t have afm

  8. If the 4th cylinder lifter has failed, would driving it damage the engine? Would you get enough power to drive at freeway speeds? Our 2013 yukon with 47k miles just failed. Having it fixed now, just curious Seems like a problematic design. Very expensive repair too!

    • Just had my afm lifter fail had to drive 500 more miles home on 7 cylinders in my 6.0 lt chev.
      Just pulled it down in the garage there was no other damage , luckily.

    • I had one fail and it chattered the cam to the point that I had to Install a new cam. Basically rebuilt most of the engine while in the vehicle. Don’t drive it if you have a dead cylinder due to afm failure.

    • Driving around with a bad AFM lifter is the fastest and easiest way to destroy an engine. A bad lifter can be a minor repair if you get it fixed immediately after you hear an issue. If you ignore it and keep driving, odds are you will destroy the cam as well.

  9. GM should recall every vehicle with this terrible design flaw! Every one of these engine will have a lifter fail, this is a travesty!

    • I didn’t have lifters fail, I had the 4 cylinders 1,4,6,7 have such blow by that my choice was a valve and piston job or a new motor. I went with the new motor for the warranty. I only had 81k on the motor. My 2002 I had over 298K on it with no engine related issues. I will be installing the AFM deactivator tonight when I get hoe.

    • I have a 2013 1500 with the LC9. has 92,000 miles and was just told I have cam and lifter failure. $8500.00 fix. Looking to tear down myself.

      • Thomas Davis says:

        My 2013 LC9 just had #6 lifter fail, got a misfire code but the ticking gave it away. Seafoam with syn oil change only fixed for a week. Getting ready to diy for $450. How did your turn out? Any problems to watch out for?Did you replace the VLOM?

      • Ron McMaster says:

        Do not pay that amount. Call chevy.They should being paying most of that.

    • I had a 2004 small block v8(4.8) 331,000 miles on the truck,it was the usual on the maintenance front axles,etc. Never did strand me on the side of the road way. September 2017, I got talked into trading for 2017 AFM this was a bad choice 5.3 engine. Only wish I’d did my homework, nothing but issues, from 14,000 miles it starts this motor noise,as if lifters at cold starts, let set up for 8 hrs same noise, this noise is on the right side of engine, it lasts 5 seconds but never heard this until we had this cold spell in the state low temperatures or it was just time for this to start? I have always loved Ford and Chevys , I don’t like this Vehicle not one bit, starring shaft has to be lubed or it whines, front A arms has done been replaced, tapping in motor, leaf springs has been lubed, retorqued, put completely new leaf springs back in on the rear , grease all down from rims to body of truck, you have to clean often,console shakes as if milk shakes in console which later they also put rubber bushings in front of coils of shocks ( front end) .You lock it down in 4×4 it s metal to metal , As of now I’m at 32,000 done gone threw all the arbitrator laws depending on how it goes? Pushing forward

    • Absolutely agree, but we all know GM can’t afford to recall them all & definitely won’t, gettin’ a Toyota, but first will go to GM dealer and ask to see a truck without AFM & when they say they don’t have it I’ll say “See ya, I have an appointment with the Toyota dealer!” Always had GM’s never anything else till now. AFM Sucks!!!

      • Toyota has their own problems. The 2016+ Tacomas are junk. So bad they’ve been rated least reliable midsized truck by consumer reports for 3 years in a row. Constant engine and transmission problems. The Tundra fares better but the frame has the rigidity of wet spaghetti and the 5.7 has had problems with VVT solenoids and the plastic timing chain tensioners. They’re also notorious for bad cam tower oil leaks.

    • What makes you think it was a design flaw ? It was well researched and tested back in the late seventies and eighties . . . Was a disaster then but a profitable disaster. Yes a poor design but a flaw ? Perhaps a flaw by design would be a more appropriate description . IMHO .

  10. AFM sucks I’m paying for a truck that has broke down twice replace the cam and lifters and now it’s broke down again 105000 miles never heard of that in a 350 Chevrolet.

    • Right with ya Chris!

    • I have a Yukon 116k it now needs its 3rd set of lifters and cam.

    • It is a bad deal for sure.ive fixed a few best thing u can do is delete it in buy kit.no sense in fixing a flawed problem with the same flawed parts.

    • Happened to me twice 2009 Silverado, finally deleted DOD and installed a performance cam and lifters. bought at Brian Tooley Racing !
      Runs better than new now and no more oil consumpsion!!

    • Chuck Hankins says:

      If I had wanted a 4 banger I would have bought one. 2018 new truck has me really disgusted If I had checked this out better, there would have been one less POS Chevy sold last year !

  11. put tran fluid in oil for a day till lifter became active, had to change the fouled plug. changed oil , its all working now, but want to disable this sorry system.

    • I’m curious as to how much tran fluid you put in?

    • Larry Chapman says:

      how much tran fluid did you use

    • Cam McKnight says:

      It actavated the lifter? The detergent. How long did it take?

      • Matthew Cribbs says:

        I used 1 quart of tranny fluid in the crankcase ran it for 20 minutes, no luck. Next day, fired it up to take the the junk yard and it ran great. Run it and let it soak overnight. I still get a P0336 code every once in a while but still good to drive around town. Would never take it on a long trip. Last GM I’ll ever buy unless it’s got a diesel.

        • You were lucky that it worked. If the lifter actually fails so that the mechanism won’t release, it won’t work. It depends on the failure mode of the lifter – however, certainly worth a try. Some guys have been able to use a tool through the top with the cover off to get it to release. You could also have tried that if the trans oil didn’t work.
          Since the tranny oil worked, you should now change the oil, right? And consider using a higher grade of engine oil like Mobil 1 or Amsoil, etc.

    • so the trans fluid worked for you then? is it still working good since you have done that with the trans fluid?

    • Just shut AFM off. How stupid do you have to be to whine like a welfare check cashing idiot when there are literally 3 or 4 different ways to totally disable AFM.

      • I have successfully used a gadget that plugs into the ODBII. Cost about $250, but it is not fool proof. Once the lifter has been damaged, the cam is probably also damaged. Then it takes out the lifter again and again until you bite the bullet and replace the cam.
        If doing that, the full blown AFM delete is about $1000 depending on how far you go (full overhaul or cam with lifters only). Once the failure has occurred, the AFM shut off methods other than that probably won’t work.
        I speak from some experience. My daughters car had about 230,000 miles when she complained of the problem. She had driven it for a couple of months that way. I pulled the head off, replaced the lifter and put the gadget in the ODBII for about $400 total.
        I told her to never pull the gadget out. She started to have the lifter problem again after 60,000 miles more. So I did the job one more time. Told her that it would not last and that she needed to find a different way to get around. She drove it for another 35,000 and it went out again. But then she passed away from cancer. I am going to do the full repair of the engine now, but not an overhaul (too hard to get at the pan). But I can replace all of the other engine parts without doing the pistons and bearings – so that is what I plan to do. If I had been able to push the issue and get the time, I would have done the full fix at first without the hassle. This is my project car and will be my drive (about 5000 miles a year).
        Because I want to.

  12. Chris Kenney says:

    I did a delete on an 07 avalanche and no have no power, any thoughts on what might be going on? I have had some say that it is the valves and others say that it is the cat’s plugged. I don’t know where to being to look for the problem.

    • Chris, when you did your delete, did you also change the cam at the same time? If you left the original cam in, the AFM cylinders will be down about 25 lbs. of cranking pressure because the duration is longer on those cylinders to being with to offset the AFM lifter design. You may eventually see a check engine light from a misfire code and the ECM dialing everything back to protect your engine.

      One alternative is to swap in one of the larger 6.0 non-AFM truck cams. If you are using VVT, you could use the NAL-12612273 (L92) cam. If you don’t have VVT, you could use part number NAL-12561721 (LQ9) along with a 4-pole 3-bolt 2005 Corvette cam sprocket p/n NAL-12586481 to make it compatible with your ECM.

      If you swapped in a LS9 cam, you will find it makes good power at the very top, but it’s actually down from 5,000 rpm and lower where the truck spends the majority of its time. If that’s the case, Summit Racing has dedicated truck cams that will increase power through the range…bottom to top…but the meat of it is in the mid-range where your engine spends the most time. Give the folks in Summit Racing’s tech department a call (330-630-0240) and they can work on a solution for you.

    • Mike Sinnett says:

      I just did the delete and replaced the cam as well. Still have no power. I have no clue what to do now. I have already dropped a lot of money on this truck (08 suburban). Any help would be appreciated.

      • Hello Mike, if you don’t have any obvious signs like check engine lights etc., there are couple different possibilities. If you installed a factory truck cam, there shouldn’t be any particular reason for it to be down on power. We recommend taking the truck to a local chassis dyno tuner and talking with them about a reflash.

        They may be able to find some of those missing ponies. If you installed a performance cam intended for a car, it may be bleeding off some low end compression. A tuner can often fix that as well by giving it some more ignition advance in these regions.

        We’ve written some articles on the various Vortec engine upgrade paths, such as this one on LQ4 and LQ9–it discusses some of the better options for choosing a cam intended for use in a truck. You can search our site by engine code to find some of the upgrade articles we’ve published and more are on the way.

      • You also need the disabler installed in your obd connector. You will be placed in derate if the ECM does not see the correct resistance from the ATF intake.

        • sorry AFM intake my bad

        • Why can’t u just unplug the solenoid on back of engine by oil pressure sensor?

          • You can unplug the sensor on the vacuum booster and it will fool the computer into thinking there is a high demand on the engine and shut down the AFM system but you will have a ‘ Check engine ‘ light in your face for doing so . Also I don’t recommend doing this as you may be in violation of some emission’s standard or manufacturers ethics code . . .or something similar .

    • Michael Badame says:

      Chris,

      I had the same issue and had to have the AFM information deleted from the computer and the car tuned.

  13. Keith Belair says:

    Question – i just bought a 2005 Saab 9-7 with 5.3 v8, (same as GMC envoy) which came with AFM, the car runs fine, so if i just install the OBDII electronic device, is it just as likely that my lifters will still go bad? Im a little confused on the problems too, I’m reading that the 2007 pick-ups with 5.3 really had bad oil consumption and plug fouling problems, but is the 2005 5.3 that came in the trailblazers, envoys, and sabb 9-7s the exact same design as these pick-ups and prone to the same failures? I guess they also went to aluminum blocks in 2007, not sure if that has anything to do with this issues… thanks for the advice!

    • Keith Belair says:

      I guess what I’m really trying to ask is,, are there any cons/disadvantages to installing the AFM delete Electronic module? You mentioned that it will shoot oil into the pan and on the cylinder walls possibly causing some oil consumption… So i have a running vehicle and my only concern is making it as reliable as possible, should I disable the AFM or not?? thank You so much!

      • Hello Keith, if your lifters are still in good shape, an AFM Disabler is a good idea. When they are locked into position, they won’t wear further and cause issues down the road.
        The vehicles affected were 2007 to Feb. 2011 AFM equipped engines (Aluminum or Iron block-L94, LZ1, L99, LC9, LH6, L76, LFA, LMG, and LY5). The secondary pressure relief in the back of the pan began to open at 55 psi and was completely open by 75 psi.
        In October of 2010, GM added a deflector (p/n NAL-12639759) to keep oil from being sprayed directly on the rear cylinders.
        Another option is to plug it entirely if the AFM is already removed. It uses a M14 x 1.5 thread plug like Dorman 65217. More information can be found in the GM TSB bulletin number 10-06-01-008g. It also mentions a valve cover replacement with revised PCV valve design.

        • Keith Belair says:

          Wow, thanks for the wisdom,, i checked my VIN Code (position #8, M=LH6) and my 2005 Saab 9-7x does have the LH6 motor with iron block,

          Are you sure it’s only 2007 & newer motors? I’ve read at many websites that the GMCs envoys, Chevys and saabs did start to come with AFM in 2005 with the LH6 motor,It says here it started in 2006 on the saabs, then the pick-ups got AFM in 2007.
          http://www.autoserviceprofessional.com/article/91652/ticking-gm-v8-lifters-and-dtc

          There is no light on my dash or anything that indicates the system is active or exists, so it’s very confusing, I’m still not sure if my vehicle has it or not. I can’t really tell from driving. I guess I might have to call a dealership or GM to get a definite answer on this one.

          I won’t bother with blocking the relief valve. a little burning oil is a minor thing, my main concern is avoiding a multi-thousand dollar repair needed to the motor.

          • Keith, we’re happy to help. The LH6 in 2005-06 was a little different than the one used in 2007-09, but both had AFM. As a side note, the early ones had a 24x reluctor and plastic chain guide (good) vs. the later ones with 58x and the spring loaded tensioner (not so good).
            There is a note in the TSB that states the bulletin doesn’t apply to the LH6 used in the Rainier, Trailblazer, and Envoy due to a different design oil pan and AFM relief valve. Because your Saab is mechanically similar to the Trailblazer, we’d suggest that you are correct and no changes need to be made to the relief valve.
            At this state, a disabler would probably do what you need it to do. You can monitor the oil level on your dipstick for 3,000 miles to determine if the deflector or plug would be needed, but chances are you won’t based on the TSB.

          • Keith Belair says:

            yep, you are 100% Right, I called a local saab shop and they filled me in, in 2005 the trailblazer and clones have DOD (displacement on demand), My next issue is getting extra ignition keys on the cheap. Apparently all passkey III keys are not the same,, I bought one that said for 2006 impala assuming all pk3 would be the same, and I could not get it programmed in my saab 9-7,, so how I’m waiting on ones that specially said for saab 9-7. hoping they will work. will feel like a jerk asking the clerk at lowes to cut them again.

        • David G Smith says:

          Brian,
          My 2011 Tahoe has a LMG motor in it with a build date of May 2011. You may want to update your post. Yesterday my motor (116,000 miles) felt like it went into “limp mode” when decelerating from 8 cyl to 4 cyl but it recovered.This is the second time that this has happened in 6 months so I think that I am on “the slope”. The “Service Traction Control” and “Check Engine” lights also came on again but went out after a few minutes. I ordered a electronic disabler for it today. In the mean-time I found that you can keep the engine from going into 4 cyl mode by using the manual shift (if so equipped) and keeping it out of 6th gear. In 5th gear on deceleration and “99” for fuel mileage estimate on the dash it still didn’t go into 4 cyl mode.
          Regards,
          Dave

          • Chris Durante says:

            I also have a 2008 LTZ avalanche with 106,000 I have the exact same symptoms at this point I just want to sell it will the disabler help remove the check engine light won’t pass inspection with light on thanks for your help Chris

          • My 2012 Silverado 5.3L just did the same thing as your Tahoe Brian. Accept i only have 60K on my truck and it hasnt recovered. I tried the trans fluid in the oil. Then changed the oil. Then had to drive the truck back to Tampa from Cheifland Fl. This happened on a camping trip with my kids last friday night. Now i have my mechanic trying to follow a YouTube video I saw with a guy and a rod and a hammer. Hopefully he can free up the stuck/collapsed lifter. Then I guess I have to spend a bunch of money and get the delete kit. This really sucks. I loved this rtuck until this happened!!

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  15. My 2013 GMC Yukon XL 6.2L is currently having a failed lifer replaced. It is being covered under warranty since I only have 72,000 miles on it. Since it is not costing me anything out of pocket, I did not go with the Delete Kit (did not want to spend the money). Once I get it back, could I install the Disabler safely. I would rather stay a V8 full time than deal with AFM issues in the future.

    • Keith, sometimes they will only replace one lifter rather than the whole set–If that’s the case, another lifter can fail again pretty quickly.
      You are correct. Install the disabler when you get your Yukon back and it will remain in good working order.

  16. Mike Fasano says:

    Brian, I just purchased and installed a remanufactured L76 AFM engine for my 2007 Suburban. We were getting a code that the cam position sensor was not functioning properly. Changing the sensor didn’t help. As it turned out one of the cam bearings was failing and causing the cam to wobble (my guess) which messed up the AFM and probably some other stuff too. The engine had 200K miles. As we were installing the sensors prior to installation in the vehicle, we noticed that there was no fitting on the oil pan for the oil level sensor. I asked my local Chevy dealer, from whom I purchased the engine, to find out why the oil pan lacked the fitting. They learned that the oil level sensor was necessary and that we were supposed to have been advised that we needed to reuse the original oil pan. Fortunately, the old engine hadn’t been shipped back to the remanufacturer. When we removed the oil pan from the new block, we noticed a metal shield covering the bottom of the block. In other words, the crankshaft and bearings were not visible. Is this the shield you referred to in a past post? Side note, after 200 hundred miles of trouble free driving the transmission failed so we had to replace that too. I am leaning heavily on installing the AFM disabler. Thanks.

  17. Scott Perdue says:

    We recently purchased an 08 Suburban and noticed some shuddering around crusing speeds, usually 45-55mph and highway speeds around 75mph. Took it to a shop and they advised that it could be due to the AFM system not functioning properly. We are looking into the AFM Disabler option, but my question is- how do we know if a lifter is already bad or not? The car runs great apart from the shuddering at those speeds. Would it be fine to go ahead with the AFM Disabler? Or is the shuddering indicative of failed/failing lifters that need to be replaced before moving forward?

    • Shawn Campbell says:

      Brian, I have the same question as Scott. I also have 08 Burb, but have different symptoms (high oil consumption, blue exhaust smoke at start, and now a really rough start after sitting overnight). How do you know if the lifter has failed? I have no other engine problems and I’d like to fix the issue. Do you think I can still disable AFM?

      • Brian, I have a 2010 burb with the exact same symptoms and questions as Shawn… please help! Thanks.

        • If a shop pulled a DTC code P0300 and found AFM to be the issue, it may not be too late to try the disabler. It will show up as a misfire code in a cylinders 1,4,6, or 7. There is a filter screen under the oil pressure sender that may be clogged and not getting enough oil to supply the solenoids. This may show as low oil pressure or code P0521 or P0523 and is a relatively inexpensive fix as well.
          As the problem gets worse, you’ll hear a lifter tick and eventually you may see clearance between the pushrod and the rocker which will quickly destroy the cam. I’d try the disabler and the screen cleaning first and do the AFM delete if that doesn’t solve the problem.

          • Thomas Davis says:

            what deleter (if that’s a real word) have you heard good things about. Ive heard the Brand name “Range” thrown around in other forums

    • Deedra Suek says:

      This is how mine started out…then 6 months later on the highway the service stabilitrak light and flashing engine light came on. Stopped at nearest gas station and found I was a quart low on oil…added oil and lights eventually went off and luckily we made it the 5 hour drive home. Next day I drove my car to work and was fine but when I left work all lights came back on and terrible noise in the hood. Took it to my dads and he tore things apart and found that I had a lifter that was stuck. He unstuck it and I took it for a drive and same thing happened. My dad ended up running seafoam through it and some transmission fluid, changed the oil pressure sensor which I definitely think was bad and also cleaned out the little screen and he said it was so full of junk and metal scraps. I have driven it now for 2 days without issue but I am having the AFM disabled/tuned out today. I am hoping this does the trick. I always have done my oil changes on time, not sure about the people who owned it before me though. Although the last oil change I had they offered a more expensive oil that would let me go every 5,000 miles and when this happened I was almost at 4,000 so needless to say I will never do that again…

  18. Eric Hansen says:

    Hi Brian,
    I bought a 2010 GMC Sierra 5.3L Truck in 2013 with 24K miles. Right now I have just over 77K miles with no lifter problems… Knock on wood… I am thinking of the AFM disabler. However I do have 7 year bumper to bumper warranty that covers this problem if I start to get lifter problems over the next 2 years.. On the other hand if get the AFM disabler installed I am pretty sure that I void the warranty from what I read on the policy. The problem I am facing is that I want to drive this vehicle for at lease another 77K and do not want to drive my vehicle with this AFM issue. What would you do if you were in my situation? Install the AFM disabler now or wait until my warranty just about to expire to get this AFM issue resolved?

    • That’s a tough call, if the warranty will cover it…I’d let it run out. As a side note, Range Technologies recommends removing the disabler between visits to the dealer as they will need to access the OBD-2 port.

  19. thanks brian love the info I’m thinking of buying a ford now

    • Larry W Seals says:

      I am going to buy a new truck in about a month it would be a Chevy but Dodge has lifter problems so they are out and Chevy has DoD problem.If they come out with Silverado without the DoD then i would buy one.But they aren’t so i will become a Ford man from now on

  20. Clinton Reed says:

    Hello. I have a 2011 Chevy Tahoe with the 5.3 Gen 4 LS (VIN Code 0) and I bought a CAM motion DOD/AFM delete kit, 3 bolt drop in CAM Motion stage 2 camshaft, VVT delete kit and finally a Diablo Predator 2 Premium for GM programmer. I was told that before I start the vehicle up I will need to have the AFM and VVT disabled in the ECU but that would require a custom tune from a tuner as the ECU cannot just be told that the AFM and the VVT is gone. I am trying to find out of this is true. Diablo says yes but they do not provide tunes. CAM motion says no just have to disable the AFM and VVT with a stock tune as the camshaft is not an aggressive camshaft but a drop in. There are no changes in the valves or the springs. I have also heard that the oil pump is to be changed and I have also heard that it does not matter. Very confusing stuff out there. Any advice that you could offer would be great. Thank you for your time.

    • A custom tune by a knowledgeable tuner with access to a chassis dyno will pay a lot of other dividends other on top of turning off afm and VVT. You will get codes thrown if the afm is physically removed without telling the ECM you did so. The tune is the best bang for the buck outside a cam swap anyway and what I’d recommend.
      The oil pump is high volume, but there are a lot of people that don’t change it and rely on the pressure valve to keep the volume manageable. The only problem is the extra spray on the cylinder models if a deflector isn’t used and this can show up as increased oil consumption.

  21. Robert Drum says:

    Have an ’06 Yukon with 5.3, original engine had bad knock, was told it was lifters so had them replaced. It was good for about 10 miles and started with same loud knock noise. Replaced the engine with remanufactured one and had the AFM turned off with a computer hooked to the ECU. Have misfire code and engine has what I would call a surge while driving. Is this due to the AFM being shut off? Didn’t really notice a loss in power other than the surging, (wondering if that’s the engine trying to switch between 4 and 8 cylinders).

    • With the AFM tuned off, it shouldn’t be trying to switch over to four cylinder mode. I don’ know what else would cause the surge, but I’d research the misfire code and see which cylinder is problematic. There may be an ignition related issue on that cylinder.

  22. I got a 09 Chevy I’ve had the 1 go out then the 7 about 2 weeks apart if I known what I know now I would’ve changed them all at once but now I have a misfire on cyl 4 but it came back in why are these lifters going out one at a time like this the 1st two that went out I was coming off the interstate an stabiltrack came on now the 4 misfired twice both times pullling out my driveway

    • Yes, always change all the lifters at once. What was happening to the first is slowly (or quickly in your case) happening to the others. Keeping the oil changes regular is important and it’s possible that a previous owner may not have been as diligent as you are.

      • Thomas Davis says:

        I can tell you for the past 2 years I changed out my LC9 5.3L fully synthetic oil every 3,000, even though Mobile Oil claims 10,000 miles or more. I have read synthetic isnt good for AFM lifters. Any truth to that?

        • I have a ‘12 wit 4.8 Silverado 75000 miles
          A 14 gmc 5.3 Sierra 85000 miles
          2 15 with 5.3 Sierras both with 100k and
          A 17 with 5.3. With 40000
          I ran 0W-20 on more the 5000 miles between changes. No problems with any to this point.

        • I have a ‘12 with 4.8 Silverado 75000 miles
          A 14 gmc 5.3 Sierra 85000 miles
          2 15 with 5.3 Sierras both with 100k and
          A 17 with 5.3. With 40000
          I ran 0W-20 no more the 5000 miles between changes. No problems with any to this point.

    • Thomas Davis says:

      Good point which begs the questuion, why does the Service Stabilitrak error seem to coincide with lifter failure? Mine did at the exact same time.

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  24. Jeff Adkins says:

    I have a 2018 GMC with the Eassist and AFM
    Should I buy one to disable the V4 mode?
    Yeh truck has 5237 miles on it
    Oil 0w or 5w -20
    Thanks

  25. Brian, we have a 2007 Yukon Denali in our shop with a 6.2L v-8 that has suffered a lifter failure with camshaft damage. We have purchased a used low mileage 6.2L as that is all the extended warranty company would pay for. My tech just installed the engine, only to notice that he doesn’t have anything to plug the AFM solenoid pack into. The owner of the vehicle has apparently owned a few of these vehicles and stated that this vehicle doesn’t have AFM…never did? He claims that GM used the same engine whether it was or was not equipped with AFM in this year and model? I phoned the dealer and gave the VIN number, told it isn’t equipped with AFM. It had the AFM wiring & lifter cover installed with solenoid pack in the original engine, we even removed it to inspect. This replacement engine has the same camshaft sensor plug plug, 5 wire like the AFM would use, instead of the 3 wire. My concern is if I leave the non-AFM lifter cover in place & have nothing to plug the 5 pin AFM solenoid connector into, will I get a MIL? Logic says that it should not as the ECM isn’t programmed to use AFM, but will it see a lack of resistance from no solenoid pack plugged in? I could just transfer over the AFM lifter cover, but it is really nasty on the bottom side & I do not want to risk damaging this replacement engine if it is loaded with debris from the lifter & camshaft failure. Then again, it should have never been controlling those solenoids. Any thoughts or suggestions would be appreciated.

    • Billy, there is some interesting trivia here on the L92. Per bulletin 10-06-01-0007b, 2007 L92 had first and 2nd design. The 1st design (built prior to April 1, 2006) was had afm components but wasn’t connected. The 2nd went with a conventional valvetrain. As you said, the ECM was never seeing the AFM so I think you’re good to go. Please report back if you have any issues, but I think you are in good shape.

      • Brian, thank you for the quick response. We chickened out though and just bolted the AFM solenoid plate onto the used engine. We figured we already had the intake manifold off to install the engine, why run the risk of MIL only to have to removed the intake manifold again without being paid. We did take it apart to check for metal possibly being trapped inside, it looked like brand new. We believe this confirmed that the AFM has never been operating in this vehicle. Thank you again for the response. 🙂

  26. Hi. Sylinder one lost compression on my 09 5,3. No movement on the rocker arms. Replaced all lifters. No it runs fine on sylinder one but not on 6 or 7!!! Pulled the inntake and replaced valleypan With all the solenoids. Did not help. Pulled right valve cover an rockers on syl 6 dont move. Well, they move a couple of times after startup thats all.Asume its the same on syl 7 on the other side.Disconected the Connector to the solenoids, no difference. Seems my oil pressure sensor is bad, are showing the same oil pressure at all times, even when it dosnt run.Dont know it that fault was there before i replaced the lifters. (Bought car 1 day before lifter died!) I asume low oil pressure cant make some of the DOD lifters to malfunction? All New lifters were from AC delco. Can they be faulty? Its not possible to install them wrong? They layed over night in engine oil before instalation. Thankfull for any ideeas!

    • Took the heads off again. On the AFM lifters that dosnt work i have installed them With the oil hole Down! Installed them again, all facing upwards, will know tomorrow if that was the solution.If this is the cause i cant beleve why they arnt build so that it is impossible to install them the wrong way in the plastic holder.And altso that there was no warning or installation advice With the New lifters.If these are the only lifters in the Whole world that must be in
      stalled in a certain way a warning wouldn be a bad idea…

      • OnAllCylinders says:

        Ketil, let us know what you find out. We’d recommend a call to our partners at Summit Racing. Their tech guys have seen it all and may have some thoughts on this as well. 330-630-0240.

  27. Hello,

    On June 4th you stated “The vehicles affected were 2007 to Feb. 2011 AFM equipped engines (Aluminum or Iron block-L94, LZ1, L99, LC9, LH6, L76, LFA, LMG, and LY5)” I am looking at purchasing a 2012 Tahoe with the LMG per the build sheet. 50,000 miles. Are you saying that I am in the “clear” by a year and issues fixed? My local mechanic suggested whatever I buy with an AFM he will send off the ECU to have the AFM flashed out. Thanks for your help.

  28. Kevin Penney says:

    I’m servicing a 2011 Chevrolet 5.3 with AFM. Truck has an active P0300 code and runs very rough. Found that all passenger side cylinders are not firing. Only running on drivers side cylinders. Driver reported this occurred suddenly while driving down the highway. Truck ran fine before that. Not sure which direction to go from here.

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  30. Brian, I repaired a 2012 GMC Yukon Denali as the AFM lifter on #4 I take failed. Everything else looked good. Replaced all lifters on passenger side as well as pushrods for even wear. Everything was fine for two weeks, ow customer complains s it same noise it made as before. What’s the next step? Replace the cam or do the delete kit?

    • There is a good chance that some of the driver’s side lifters decided to go. It does seem that when they start going…they go quickly.

      There is a chance the cam lobe was stressed and started to deteriorate. That might show up if you cut the filter and looked for debris in the pleats. But yes ultimately, it might be time for a cam and any AFM lifters that weren’t replaced. I’m always sorry to hear when people run into issues like these.

  31. 2015 SILVERADO 1500 4×4 crew cab with 5.3L engine:

    So two weeks ago with approx 70K miles, I had an odd noise when accelerating and then engine light flashing and riding rough. Took it to the dealer and was told I had a “collapsed lifter.” I had purchased an extended warranty when I bought the truck new. Glad I did. Covers me to 100K. They replaced all the lifters, said no other damage, problem lifters were on cylinders 6 and 7.

    Shame this happened. Love the truck. Have an intake and Borla exhaust. Don’t want to make a move on a new truck or jump to a 2500 yet.

    Open to suggestions about best course of action. Delete the AFM, buy a tuner/chip, take it to a performance place and get an actual “tune” done that fixes it, replace the AFM lifters with non AFM type, change other engine components with this……etc…..etc…..etc…???

    If buying a “tuner/chip” which works best for that truck/engine?

    Thanks for any input/suggestions.

    Respectfully,
    Jim

  32. Have a lifter problem on my 2010 5.3 Silverado. Happened once 1yr ago, truck was not used for a week and worked fine when i started it back up. Now the problems back, I have 180k miles on it now. Jusy 3 weeks ago I quit driving it because of the lifter, but it worked fine when i started it back up. No clue what to do. The lifter seems to recharge whenever the truck sits for some time.

  33. Hello! I’m considering just replacing the 5.3 ( should be LMG, 2007 YUKON ) with the L96 crate engine. Can you tell me what needs to be done with the VVT?

    If possible, will simply not using VVT provide a powerful,good running engine?

    Thanks in advance!

  34. Dean Davidson says:

    I have a 2007 Gmc Envoy Denali with LH6 cant find a good LH6 engine but I found a 2011 LC9 engine w 52000 miles will everything plug up or what am I getting into?

  35. Hello Brian, I just purchased a 2018 Silverado with a 5.3 AFM engine, I have 200 km on it. I traded in a 2004 4.8 L with 256000KM on it that ran like a clock and never gave me a problem. After reading these forums I’m a little concerned about my decision to stay with GM. Do you think it would be wise to put a AFM disabler on a brand new truck to avoid engine damage? Should I wait until the warranty runs out, or will that be too late to stop possible damage? Does the disabler prevent the engine damage in the first place?

    Thanks in advance!

  36. I bought a new 2017 Cadillac CTS back in January – 3.6L V6 with 8-speed trans. I love the car so far. I’ve been a Ford guy my whole life, so I was unaware of AFM until a recent trip where I did a lot of highway driving and happened to bring up the real-time mpg display, where I saw it switch between V6 and V4. I was getting ~ 30 mpg, so I love that. But after reading this thread, I’m a little concerned about the long-term reliability.

    Is this an issue only with GM SUVs and trucks, or does it include cars too?

    I only have ~ 5k miles on it, and it hasn’t been driven hard, so I’m assuming the lifters are fine. Given that, would you recommend buying one of the OBD-II devices to disable AFM? Is there any potential down-side to doing this – in other words, might this do more harm than good?

    Thanks!

    • Dee Watts says:

      I am wondering the same thing. I just bought a 2018 Silverado. It has 8,000 miles on it. I just took a long trip and it used 1.5 quarts of oil. I’m confused from the write up about the plug in. Will the plug in cause my truck to burn more oil or will it fix the oil consumption issue? Why have you not gotten a reply from Mr Nutter

  37. Gary keeling says:

    Buying a Silverado 6.2L. It’s a CA EMMISIONS TRUCK. Will this AFM DISABLER damage anything???. Friend will send to me from Arizona. Thank you. Gary

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  39. Brian, I have been reading your article about the AFM. I had a 2007 Yukon XL 5.3 with the AFM. Traded it with 180K miles and did not experience any problems. In 2015, I purchased a new Tahoe with the AFM and two weeks ago with 71K miles on it, the engine light came on. I wear hearing aids, but I thought I heard more engine noises, but after checking the gas cap, the light went out for a week. It came back on last Wednesday starting with a flash. I called my service station and they told me to get it in ASAP. I did and they diagnosed it as being on Cylinder 3, not one of the cylinders that deactivates. Anyway, after some pushing and pulling I took it to the Dealer who sold it to me. They took the engine down today found so much damage inside they ordered a new engine from Detroit. My question is: do I install the electronic disabler on the new engine to avoid future issues?

    • I would. From what I’ve read new and low mileage engines with no issues is ideal to do a afm delete, tune, or use of a disabler.

  40. I have a 2008 Buick Lacrosse super that I am having a hard time finding a tuner or a tune shop that can turn off the afm. HP tuners is not for someone like me that doesn’t know how to use it and from what I read neither the range nor diablo plug and play device will work since the buick’s pcm files are different than all other GM vehicles that came with afm because it was tuned in house at gm’s performance division. any help?

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  43. Hi Brian please help, yesterday after ice fishing was climbing a hill back home and check engine light flashed. Took it in this morning and mechanic said cylinder 6 misfire, he said the lifter hasnt failed. He used seafoam and changed to synthetic oil. Now im thinking of buying a disabler asap, am i in the clear to do so without the oil splashing problem? I have an 07 Silverado 1500 ltz.

  44. A lot more info with the ongoing GM 5.3l AFM engine issues on Cargurus.

    https://www.cargurus.com/Cars/Discussion-t30884_ds822284

    Seems like the AFM disabler device is working for a number of people including myself as the 5.3l AFM engine has inherent design faults. If you already own this engine you will need to deactivate the AFM system or even better DO NOT buy any GM vehicle with this engine.

  45. My question on a 2007 Chevy Tahoe 5.3 AFM
    Replaced all 16 lifters due to collapsed lifter on CYl #4.
    Also replaced push rods rocker arms and rocker plate guide because if wore push rod and crack in rocker arm.
    Put everything back together proper torque, gakets, valve seals, etc.

    Engine starts but is throwing a misfire on cyl’s 4,7. Fouls those plugs. New plugs and wires. Plugs spark fine engine has power at higher RPM’s although it is still in Limp mode / stabilitrack message, even after driving it a few times above 60 MPH then clearing errors with handheld programmer. 4,7 plugs foul runs rough at idle.

    Would installing the Disabler solve this?
    Are there errors or something only the dealer can clear?

    Battery was unplugged for a week..
    Really could use some pointers. 190k on the motor always ran AMSOIL full synth since new. Had similar problems under warranty, no telling what they rigged me up with at the dealer. HELP

  46. 2012 5.3 Tahoe AFM, #4 lifter collapse,replaced all lifters,started engine ran ok, then rough, got #6 misfire code. Both #6 lifters only move when turning engine by hand, if you use the starter they stop moving. Unplugged AFM engine only runs on 4 cylinders #2,3,5 and 8. Engine oil pressure is fine.

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  48. I have 2007 5.3 it’s a new motor this truck scares me 9000.00 these trucks are jokes
    Lost number four
    The lifter came apart and chewed up the lobe on the cam I’m selling it I also told my friend at work when he asked me about my truck .I said I’ll never by another GM ever

  49. I just got a 2013 Silverado extended cab 4X4 with 124,000 miles on it. the body is in great shape.

    I didn’t even think about AFM until I got to drivee it on the highway and encountered the 4 cyl syndrome.
    I have only put about 600 miles on it and noticed that the oil was a bit low and am hoping that it was that way when I picked it up.

    I have ordered an ATM disabler and will be putting a can of Textron in the gas at the next fill up. It looks as if I’ll need to start saving for a complete AFM delete kit with a new cam.

    I am a long time GM fan but after reading how they messed up the 5.3 ( I had a fantastic 2003 Z72 off road) I’ll look else ware for my next vehicle

  50. i just bought a 2018 Silverado with the 5.3
    I want to put a AFM disabler in it what all do I need to have done.

    • Hi Mike,

      I am considering the same. If you scroll back, you will find that it is recommended to change lifters and camshaft and looks some more. I will keep reading and take notes. I would appreciate it if you let me know how you make out.

      Ralph

  51. John Sallis says:

    I just bought a 2015 5 3 17000 miles I was thinking about eliminating the 4-cylinder if I delete it with just the programmer will it hurt my motor?

  52. S.Burdgick says:

    Replacing engine due to issues caused by AFM. Also putting in a new transmission vs. rebuilding.
    I plan on getting a tuner to disable the AFM. Can I (should I) also change to a standard volume oil pump? I don’t plan on installing the delete kit at this time.
    2011 Chevy Avalanche LTZ

  53. Bought an ’07 GMC Yukon 5.3 with the AFM, 87k. Loved the looks and interior and thought a I got a great deal at $6k even. One month to the day driving on the highway got the ‘Service Stabiltrak’ message quickly followed by the misfire code. After taking a $3.6h bath on the lifter/valve work and doing a little research, how can GM allow a problem like this AFM continue from ’07 to present? Can’t believe they haven’t fixed this in a decade. At least Dodge admitted they had junk transmissions in the early 2000s and picked up sales each.

  54. I have a 2011 GMC Sierra 1500 with the 5.3. There has been a lifter noise since I bought the truck 1 year ago. I have been assuming this is just a slow to pump-up lifter or lifters. I quites down to nothing after running for about a minute. I wii be using this truck to haul a camper for full time RV living and am thinking of a tuner to shut off AFM and maximize performance and economy. Most of all, my concern is reliability. I would appreciate any feedback.

  55. I have an ‘08 Suburban that is currently getting the lifters replaced a second time within a three month span. Would doing the disabler option once I get it back be the right one?

  56. Does anyone know how to disable the new Dynamic Fuel Management on the 2019 Silverados?

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  61. This is in response to pretty much everyone. I own a reputable repair shop. I have seen more internal engine failures in the last 5 years or so than I have in the first 15 years in the business. The biggest problem is nobody changes their oil on time. I would say maybe 5% of my customers keep up on their oil changes. There are so many moving components in an engine these days as opposed to the past. Clean oil is crucial. I can’t stand seeing customers continuously going thousands of miles over on the oil and wonder why there’s problems. I service plenty of these vehicles with AFM, and the ones I have to open up the engine for repair because of a failure doesn’t surprise me anymore. The oil is baked on to every component. When an engine is contstantly running on oil that is broken down, it not only where’s out components because of no protection. But it also restricts passages that the oil runs through. There are so many more oil passages on engines these days. You cannot compare them to old 350’s. Unfortunately because of emission standards nowadays, manufacturers cant go back to those style of engines. So for all of you that continue to complain about how bad these things are. Change your oil. Because it’s not just GM that have engine problems. It’s Chrysler and Ford. I have a 2014 Silverado with a 5-3. It’s got a hundred forty-five thousand miles on it. When you drain the oil at three to four thousand miles it’s still clean. Have not had a problem yet. CHANGE YOUR OIL!!!!!

  62. Why doesn’t anyone make an aftermarket set of replacement AFM lifters that are the right length but DO NOT COLLPASE! Correct me if I’m wrong- If such an item was available couldn’t you then just replace the lifters in the 4 AFM cylinders and then just run a disabler or have your ECM/PCM reprogrammed to have AFM disabled permanently. From what I am reading this would eliminate the possibility of failure, prevent false check engine lights and continue to make the appropriate power??? Only issue might be the oil consumption due to pressure run off and spraying of oil in crankcase?

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  65. All these comments on the 5.3 are blowing my mind!!!. I have a 2011 GMC with over 162,000 miles on it and it runs great! My fear now is not will it happen but when! I am not in a position to have a new cam and lifters installed but I’m also not in a position to not having a running truck!

    • Deedra Suek says:

      I would just have the AFM disabled (tuned out) then. I am having that done today on my 08′ Suburban and it’s only costing me $225. I’m crossing my fingers it does the trick!

  66. Dee Watts says:

    I am confused about the plug in disabler. I recently bought a 2018 Silverado 5.3L with AFM. It only has about 9k miles on it. I recently took a long trip and it burned 1.5 quarts of oil. The write up confuses me. Will the plug in deactivater fix the oil consumption or will it cause more consumption?

  67. I have an 07 Yukon with 230k on the engine. I had #4 lifter stick and now i am looking at replacing the engine with a non-dod version. My 5.3 has a vin code of O. Did gm make a non-dod version of the 5.3 with iron block that would work in my application? If so what would the vin code be? If i am successful locating a non-dod vin would i just need to have the ecm reprogrammed?

    Thank!

  68. Steve gallagher says:

    i have a 2007 suburban 6.0 and the number 4 intake lifter took a dive.i have already started to disassemble the engine as i plan on replacing all the lifters and reassemble the engine as i never had any other problems with it. the vehicle has 120,000 on it and 30 to 60 psi of oil pressure never lower or higher. i’m going to plug in a dissabler when i’m done to keep it V8 mode all the time. in your opinion will this work, i really don’t see any reason it wouldn’t. please respond with your opinion

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