How to Diagnose an Engine Misfire
An engine misfire is an issue that you can’t ignore. Not only does it usually cause a loud noise to come from your vehicle, but it can also cause a lot of bucking and shaking.
When this happens, a cylinder is unable to burn the air and fuel mixture efficiently in the combustion chamber. Then your emissions and fuel consumption levels rise.
Common Causes of an Engine Misfire
Since a misfire happens when one or more cylinders fail to fire correctly, the combustion process has changed in some way. Diagnosing the problem usually means your mechanic will go through a checklist of common issues.
You may have experienced a component failure in the ignition system. There could be a vacuum leak, a problem with the fuel system, or a compression drop that occurred.
It can also happen when there’s an issue with the valves or sensors that the computer uses to calculate the proper air-fuel ratio.
Many of these issues are repairable. When a misfire occurs because there isn’t a spark present, then the unburned fuel can find its way to your exhaust system and destroy your catalytic converter.
It helps to gather as much information about the symptoms and circumstances of the incident so that your mechanic can reach an accurate diagnosis. Does it backfire only when the engine is cold, or when it warms up?
Do you have a backfire when you accelerate, or does it happen consistently?
Even something as simple as a loose electrical connection or hose can be the cause of this problem, so try to relay as much information about the maintenance history of the car when you bring it in for an inspection.
What Are the Symptoms of an Engine Misfire?
You may notice one or several symptoms begin to appear while driving if your engine experiences a misfire. The one that most people recognize immediately is a popping sound. Although it can be quite loud, it doesn’t have to be. If your engine sounds different than what you normally hear, then it might be time to bring it in for a look.
Sometimes the exhaust or intake manifold also backfires.
An engine misfire can also make an engine challenging to start. It may lose power while driving or cause your fuel consumption to spike. You may notice jerks, vibration, or lagging that eventually corrects itself.
Some engines can stall when they experience a misfire.
The car’s computer is a valuable source of data during the diagnostic process. You’ll find one or more Diagnostic Trouble Codes associated with misfire activity. When you pair the results with the information from this guide, then it may be easier to get to the root cause of the problem.