Causes of an Engine Miss

by Wade Shaddy
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Engine misfiring usually results from simple, easily fixed problems. Engines most commonly begin to run roughly or miss as a result of wear and tear on components, which you can find at your local auto supply store. The problem usually stems originally from water, dirt or wear and their effect on engine performance.

Fuel Injectors and Water

Fuel injectors become dirty. They clog and prevent cylinders from receiving enough fuel. For a simple solution to this problem, run injector cleaner through the system. If it does not stop the misfire, the injectors may require cleaning or replacement. Water that condenses in the gas tank and enters the fuel can also cause an engine to miss; add a water-removing product to the gas to remove the water.

Spark Plugs

Spark plug failure is the most common cause of engines misfiring. Spark plugs corrode with exposure to carbon; this build p on the electrode inhibits the spark or prevents it altogether. Spark plugs can also become fouled by a rich gas mixture, or oil from leaking cylinders. To remedy this problem, install new spark plugs.

Spark Plug Wires

Bad spark plug wires also cause engines to misfire. This problem can often prove difficult to diagnose because the outside of the wires may look fine. The wires contain a graphite conducting wire that can break, however. Other plug wire problems can result from a wire developing small cracks or burns from hot engine parts. Moisture enters the wire, causing it to lose conductivity and in turn causing the engine to misfire.


Fuel filters become dirty, which can cause the engine to misfire due to lack of fuel to the cylinders. Fortunately, you can change the fuel filter easily. The air filter can also cause your engine to misfire; a dirty air filter causes the engine to receive a bad fuel mixture, resulting in misfire. Dirty fuel filters can also foul spark plugs. Change your fuel and air filters to allow your engine to run more smoothly without missing.

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