Why is My Engine Misfiring?

A misfiring engine can cause everything from sudden jolts to loud sputtering noises to an almost immediate, temporary loss in power, all of which can be extremely frightening when driving down the road. So before this happens, it’s important to know what misfiring is, what it means, what causes it, and perhaps most importantly, what you need to do in order to prevent it or stop it from happening again. We’ll take a look at each of these points in this blog.

*Editor’s Note: This blog was originally published in 2016 and updated in May of 2019 to include new information and provide additional clarity on different topics.

What Is an Engine Misfire?

An engine misfire is the name for what happens when the expected combination of air, fuel, and an ignition spark doesn’t combine under pressure to create the intended explosion which makes your engine work. Instead, you get a premature or late explosion, or explosion which creates that loud, unexpected pop. This abnormal explosion is what is known as a misfire and causes your entire car to potentially suffer for it.

What Causes an Engine Misfire?

An engine misfire can be caused by a number of different things. After all, your engine depends on dozens of parts and systems working together simultaneously with precise timing in order to function as intended. When you think about it, modern engines working so reliably and smoothly for as long as they do with such high demands on timing and part integrity is nothing short of a modern engineering miracle.

As you might imagine, this means there are several different things that are pretty common causes of misfires, but they can pretty much all be classified into one of three different categories: your fuel system, your ignition system, and or another mechanical cause.

Your ignition system: When air and fuel combine in your cylinder, they need a spark in order to ignite them and cause the explosion which provides you with the power you need. When they don’t get that explosion, the cycle still continues, and more air and fuel combines. In most cases, this simply means you have a faulty or intermittent spark plug (an issue with the ignition coil is also very common). As spark plugs wear and corrode, they lose their ability to ignite on command. In most cases, replacing your spark plugs will solve a misfire problem. You should also check your ignition wires to make sure they haven’t corroded or worn out. These are also simple and inexpensive to replace.

Your fuel system: If your ignition system checks out, then move on to your fuel system. Misfires related to fuel system issues are far more noticeable at idle or low-speed driving than they are at highway speeds. A misfire could be caused by not enough fuel getting into your cylinder, leading to an oxygen-heavy explosion. There’s also a slim chance you could have simply filled up your car with a tank of gas that has gone bad. There are a number of components that regulate how much fuel enters a cylinder that makes sure it works correctly. We recommend visiting a trained technician to evaluate all possibilities.

Mechanical system problems: Finally, mechanical issues could be what are causing your misfire. First, check your vacuum lines connected to the intake manifold to make sure they aren’t leaking or cracked in some way. There’s also a chance your timing belt or chain may have jumped or slipped. Whatever your mechanical cause may be, these are not problems that simply go away on their own.

If your car is experiencing any of these issues it’s best to seek professional help immediately because an engine misfire is a serious problem.

About Christian Brothers Automotive

When your engine is having a misfire problem, Christian Brothers Automotive can help you get it fixed. We have trained and certified technicians that service all vehicle makes and models. We pride ourselves on customer service, ensuring you receive an auto repair experience that greatly surpasses your expectations and leaves you completely satisfied. Plus we even make getting your repair simple with a free courtesy shuttle and comfortable waiting area!

Got a misfire problem? Find your local Christian Brothers Automotive today.