Top 5 Causes of a Car Misfire: The Most Common Issues


When a car has a misfire, it means that internal combustion in the cylinder did not finish completely. The car will still be able to run and you’ll be able to drive it, but you’ll start to notice the engine jerking a lot. This could be followed by exhaust smoke coming out of the tailpipe, the smell of gas, and loud popping sounds. When you experience these symptoms, it is best to get your vehicle examined by a professional right away. If you let them go for too long, it could end up damaging your engine.

The Top 5 Causes of a Car Misfire

There are lots of reasons as to why a car would misfire in the first place. To help you understand what might have been the cause of your car misfire, below are the top 5 causes that someone could experience in this situation.

Read also: 5 Causes of a Car Engine Stop while Driving

  1. Air to Fuel Ratio Imbalance – One of the main reasons for an engine misfire can be attributed to an imbalance in the air to fuel ratio within the internal combustion chamber. This usually means there is not enough fuel and too much air being mixed together. For the combustion to be successful, the mixture needs more fuel than air. Otherwise, you will notice the engine misfire while you remain idle. But when you’re driving at faster speeds, the symptoms of the misfire will go away. The reason there may be an imbalance could be due to a bad fuel pump, clogged fuel filter, or a bad air flow sensor.
  2. Ignition System Issues – There could be a problem coming from any one of the components in the ignition system. Perhaps the spark plugs aren’t creating an adequate spark for the internal combustion chamber. You could also have a worn-out ignition coil, ignition cables, rotor, or distributor cap. If any of these problems exist, the internal combustion chamber’s air and fuel mixture won’t be able to ignite properly. The weak spark will cause an engine misfire, but you might not notice right away. But as you operate the vehicle, you’ll feel its jerkiness very well.
  3. Transmission Issues – There are times when the misfire might not even come from your engine. It could come from the transmission instead. If your car starts to jerk around like an engine misfire had occurred, your transmission may not be able to adequately shift up or down. You will notice this more when you’re driving at faster speeds. This is a bad situation like any other misfire and you need to have it repaired right away.
  4. Mechanical Problems – Your vehicle is made up of many mechanical parts which contribute to the functionality of the engine. There are piston rings, camshaft lobes, valves, and cylinder walls. If any of these parts were to get worn out, it could cause an engine misfire. The same goes for when there’s an intake manifold gasket leak or a head gasket leak. Other possible mechanical issues may include a bad fuel injector or damaged rocker arms. Check the timing belt to see if that’s installed correctly too because it may have slipped. You will know when there’s a misfire caused by mechanical issues because there will be a thumping feeling from the vehicle that will never go away, regardless of your speed.
  5. ECM Problems – Sometimes there may be a glitch in the engine control module or the central computer of the vehicle which manages the engine. Any minor glitch there could throw off the combustion process and cause a misfire. Fortunately, there is an easy remedy to this type of problem that works most of the time. If you simply disconnect your battery and then reconnect it, this should solve any minor glitch or bug in the computer system. If the bug still exists after that, then you need to have the central computer examined at the dealership where you got the car.

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