Common Causes of Engine Misfires

Common Causes of Engine Misfires

28th Mar 2018

engine and oil dipstick

Engine Misfires

Is your car's engine misfiring? As you may already know, this phenomenon is characterized by a missed combustion cycle. Normally, the engine ignites the fuel and air mixture at specific intervals in the combustion chambers. There are times, however, when an engine will miss one of these ignitions, resulting in a misfire. So, what causes engine misfires, and how do you fix it?

Worn Spark Plugs

One of the most common causes of engine misfires is worn spark plugs. Spark plugs are an essential part of the vehicle's ignition system. They are responsible for creating the spark needed to ignite the fuel and air combination in the combustion chamber Over time, though, they'll wear down to the point where they can longer create a strong spark, which may result in engine misfires.

Compression Leakage

Compression leakage can also cause engine misfires. This occurs when some of the engine's compression -- exhaust -- leaks from the cylinder instead of traveling to the catalytic converter and out the exhaust. Compression leakages are usually the result of either a blown head gasket, warped head or cracked block. If you suspect compression leakage is causing your engine to misfire, consider a leakdown test. During a leakdown test, the mechanic will force pressurized air into each of your engine's cylinders to see whether or not it holds. If the air holds, the cylinder is sealed. If the pressure drops, the cylinder is leaking.

Sensor Malfunction

Of course, another common problem that can trigger engine misfires is a sensor malfunction. If your oxygen (O2) system is malfunctioning, for instance, it may cause your engine to run lean or misfire. The O2 sensor sends data to your car's computer, telling the engine how to read. If it sends incorrect data, however, it may cause performance issues like misfiring.

CEL Codes

If you haven't done so already, look at your car's dashboard to see if there's a check engine light (CEL) activated. Depending on what's causing your engine to misfire, it may trigger a CEL code, in which case you can use a scanner to read the code and identify the problem.

Don't ignore engine misfires. Whether it's happens once a week or every time you start your car, you should take immediate action to diagnose and fix the problem. When neglected, an otherwise small problem could snowball into something bigger that's more difficult and expensive to fix.

engine misfire graphic