Learn how worn or damaged spark plugs and ignition coils could cause misfires in a Ford F-150. We explain the symptoms and how proper diagnosis helps reduce the risk of expensive engine problems.
Every cylinder in a Ford F-150’s engine relies on consistently timed ignition of the fuel-air mixture to produce smooth, efficient power. If a single spark plug fails to fire on time or doesn’t fire at all, it can result in a misfire. Left unchecked, excess fuel and problems with the combustion cycle can damage other engine components as well as the exhaust system.
All spark plugs have a finite lifespan and will start to wear with time, especially if they experience high temperatures and pressures from being frequently driven under heavy load. As it ages, the electrode gap may change or corrode. Carbon deposits could start to build up, and the plug may eventually struggle to produce a strong, consistent spark.
At the same time, the spark plug also needs consistent electrical charge from its dedicated ignition coil. Trying to determine if a misfire is caused by a faulty coil or a bad spark plug typically requires professional tools and training.
When one or more spark plugs are nearing the end of their service life, you might notice misfires, the engine running rough, strange fuel odors in the exhaust and stalling problems. This is even more likely to happen under load when you accelerate hard or tow something with the F-150.
You might also notice the check engine light flash for a moment when the F-150 misfires, then turn itself off again when the misfiring stops. This can lull you into thinking it was a one-off problem, only to have the misfire happen again a few minutes later.
Yet, these symptoms don’t automatically confirm a spark plug problem. Problems with one or more ignition coils, fuel delivery issues, vacuum leaks, and even a faulty sensor could produce similar symptoms. Our thorough inspection process tests each of these potential faults to determine if your F-150 has bad spark plugs or another issue.
Typically, if one spark plug is bad, we recommend replacing all of them to ensure each one fires precisely on time. Also, when one spark plug is fouled, it usually won’t be long until others have a problem causing even more misfires. In some of these cases one or all the ignition coils might also need to be replaced, which tends to save you money in the long term.
Ford has different recommendations for when spark plugs should be replaced for different model years of F-150. This will usually be done as part of a tune up, which helps restore the engine’s power and performance.
We want you to understand what your F-150 needs before we move forward with service. So, we make sure to share all the diagnostic results and give you our best recommendation on what needs to be repaired and replaced to prevent further misfires.
If your Ford F-150 has been misfiring or showing other signs of a potential spark plug problem, call M & R Automotive to schedule an inspection. We’ll inspect the engine, spark plugs, ignition coils and all the related components to keep your truck running reliably.
