Six Possible Causes of an Engine Misfire

You notices that your car is shaking while idling. The guy at the auto parts store hooks up his car scanner and it reads a misfire on cylinder four. Why is this problem happening?  There are many potential causes of an engine misfire. If your car engine has a misfire it’s best to have a professional mechanic diagnose the problem.
Your mechanic may find one of these issues when diagnosing a misfire:

Ignition System Issues

Most of the time when you hear the term misfire you think of worn out spark plugs. What you don’t realize is that spark plugs are only one part of the ignition system. A ignition system in most modern cars contain a variety of components, including the engine control module, crankshaft position sensor, coil packs, wiring and the spark plugs. problems with any of these parts can result in one or more engine cylinder misfires.

Air and Fuel Delivery Problems

Spark plugs ignite a mixture of air and fuel inside the engine cylinders. This ignition sets the engine in motion, creating the force needed to propel your car forward. Any issue that changes the proper air/fuel mixture – From a failed fuel injector or even a vacuum leak, can cause a misfire.

Emissions Equipment Problems

Emissions equipment helps minimize the amount of pollution released into the atmosphere. Late-model cars have an array of emission equipment including the exhaust gas recirculation (EGR) system and the positive crankcase ventilation (PCV) system.  The emissions equipment when not working properly can create issues with the engine’s air/fuel mixture creating a misfire.

Sensor and PCM Problems

Vehicles today contain many different sensors. The PCM uses these sensors to maintain control of critical engine functions, such as spark timing and fuel delivery. Sensor problems can contribute to an engine misfire. In rare cases a problem with the PCM can also cause a misfire.

Engine Mechanical Problems

Engine mechanical problem can also cause a misfire. Each engine cylinder contains a piston that compresses the air/fuel mixture to create combustion. The cylinder has ring around it to seal it off, so when the piston is moving upward it creates the proper compression. Internal engine problems can keep the cylinder from sealing properly. This in turn leads to a loss of compression and an engine misfire.

Electrical Circuit Problems

Input and output engine management parts including; sensors, ignition coil packs, etc. are connected via electrical circuits. Problems such as damaged wiring or a loose connection within these circuits can also cause an engine misfire.