P0301
PowertrainIgnition Misfirehigh severityCylinder 1 Misfire Detected
What P0301 Means
The PCM has detected a misfire condition specifically in cylinder 1.
Symptoms
- Check Engine Light
- Rough idle
- Vibration
- Loss of power
- Fuel smell from exhaust
- Poor fuel economy
Common Causes
- Worn or fouled spark plug #1
- Faulty ignition coil #1
- Damaged spark plug wire
- Faulty fuel injector #1
- Low compression cylinder 1
- Vacuum leak near cylinder 1
Diagnostic Steps
- Swap ignition coil #1 with another cylinder to see if misfire follows
- Inspect spark plug #1
- Test fuel injector #1
- Check compression cylinder 1
- Check for vacuum leaks near cylinder 1
Where to start: Try swapping coil first. If misfire follows the coil, replace it. If not, check plug, injector, then compression.
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