5 Causes of Car Engine Misfire (Updated)

Last Updated on November 24, 2019 by themechanic

It is common knowledge that the internal combustion engines of cars have cylinders in them. The average engine in a modern car has anywhere from 3 to 8 cylinders. It is inside these cylinders that the internal combustion of the air and fuel mixture takes place. The more cylinders an engine has, the more power it is able to generate for the demands of the vehicle.

Sometimes there are situations where one or more cylinders are unable to complete the combustion process for whatever reason. If this happens, the vehicle may or may not be drivable. If you are fortunate enough to be able to still drive it, there will be a lot of uncomfortable symptoms to deal with. The engine may jerk profusely, and exhaust smoke may visibly emit from the tailpipe.

As the problem gets worse, there will be annoying popping noises that will keep getting louder. You may even smell gasoline inside the passenger cabin too. These are all symptoms which indicate an engine misfire has taken place. Do not let the symptoms progress because they will not go away on their own. You must take your vehicle to a licensed mechanic and have them examine the problem. Otherwise, your engine may get permanently damaged.

5 Common Causes of Car Engine Misfire

There are several possible causes of a car engine misfire. Some of them are costlier to fix than others. When you examine the list of the top 5 causes of a car engine misfire below, it can help you determine whether you have one or more of these situations happening with your vehicle. That way, it will be easier to diagnose the cause of your own car engine misfire problem.

1) Bad Ignition System

If there is a problem anywhere in the ignition system, it will likely cause an engine misfire. This could include bad spark plugs, bad ignition cables, bad ignition coils, and/or bad rotors. All it takes is for one of these components to get worn out or damaged and the entire combustion process gets ruined. You won’t know exactly which component it is until you have a mechanic inspect your ignition system to find out.

2) Engine Control Module Issues

The engine control module is the central computer which communicates with all the sensors and systems of the vehicle. More importantly, it manages the actions and conditions of your engine. You may have a healthy engine but if your engine control module is acting faulty, then it could have a negative impact on your engine. There could be a mere glitch in the module which causes an imbalance of air and fuel in the combustion chamber. Anything like this can cause an engine misfire easily.

3) Abnormal Air-to-Fuel Ratio

Without a proper balance of air and fuel in the combustion chamber cylinders, there will be an engine misfire for sure. There are several reasons for having an abnormal air to fuel ratio. Some of these reasons include a bad air flow sensor, bad fuel pump, or blocked fuel filter. You need to fix or replace the necessary component to restore the ratio back to normal. Otherwise, misfires and poor acceleration will be common.

4) Mechanical Issues

There are several mechanical components in a vehicle which contribute to the engine’s operation. Some of these components include the cylinder walls, valves, camshaft lobes, and piston rings. If one of these components goes bad, then an engine misfire is likely to follow. Sometimes a leaky head gasket, bad rocker arms, or leaky manifold gasket could be the problem too. A mechanic can pinpoint the mechanical cause of your engine misfire after they examine the vehicle.

5) Bad Fuel Injector

The fuel injector is responsible for spraying the proper amount of fuel into the engine at the appropriate time. If the fuel injector does not spray enough fuel into the chamber for proper combustion, then it will cause an engine misfire.

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