Spark plugs that are not properly gapped can lead to a misfiring, inefficient engine. Whether you’ve made serious performance modifications to your vehicle or simply enjoy your daily driver running right, it is important to gap your spark plugs correctly.

What is the proper gap for your spark plugs and vehicle application?

That depends. If this is for your daily driver, your owner’s manual will tell you that information. If you have made modifications or installed power adders, you will need to make adjustments to your spark plug gap.

If you’re not using brand new spark plugs, the first thing you will need to do after removing your spark plugs is inspect and read them. Learn how by reading our post on How to Read Your Spark Plugs.

If you are using new spark plugs, don’t assume the plugs are all gapped the same, or to factory specs right out of the box. The jostling that takes place during shipment can cause the gap between your ground strap and electrode to close.

Whether you need to close the gap or widen it, there are several spark plug tools that can help you set and measure the gap quickly and properly. This installment of Summit Racing Quick Flicks, for example, is a great tool for learning how to properly gap your spark plugs. Check it out:


Author: Matt Griswold

After a 10-year newspaper journalism career, Matt Griswold spent another decade writing about the automotive aftermarket and motorsports. He was part of the original OnAllCylinders editorial team when it launched in 2012.