Cylinder 4 Misfire Detected
Plain-English meaning
The engine control module (ECM) has detected a misfire in cylinder number 4, meaning that cylinder 4 is not firing properly during engine operation.
What to check first
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What not to replace yet
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Stop driving when
If the engine runs very rough, stalls frequently, or if there is a noticeable loss of power that affects safe driving, stop driving and seek professional diagnosis.
Related symptoms
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Owner steps
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Likely causes
Faulty spark plug in cylinder 4 (medium)
Bad ignition coil or ignition coil pack for cylinder 4 (medium)
Fuel injector malfunction or clog in cylinder 4 (medium)
Vacuum leaks near cylinder 4 (medium)
Low fuel pressure or fuel delivery issues (medium)
Compression problems in cylinder 4 (e.g., worn piston rings, valves) (medium)
Wiring or connector issues related to ignition or fuel injector circuits (medium)
Faulty ECM (rare) (medium)
Shop steps
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Follow-up questions
When did you first notice the check engine light or symptoms?
Has any recent maintenance or repairs been done on the ignition or fuel system?
Are there any unusual noises or smells coming from the engine?
Is the engine running rough at idle, under load, or both?