Fault-Code Library · Combustion
P0301: Cylinder 1 misfire detected
The ECU detected repeated combustion misfires on cylinder 1.
Common symptoms
- •Shaking idle
- •Flashing warning light
- •Poor acceleration
- •Fuel smell
Likely causes
- •Ignition coil or spark plug fault
- •Injector problem
- •Compression issue
- •Air leak affecting one cylinder
First checks
- •Avoid heavy driving if the warning light flashes
- •Swap coil or plug only as a controlled test
- •Check injector, compression, and leak-down if the fault stays on cylinder 1
Important
Active misfire can overheat and damage the catalytic converter.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
Related research
Continue your research
Move from brand context to exact model, powertrain, fault-code, and buying-checklist evidence.
Buyer help
Request a used-car risk review
Send us the model, year, engine and mileage. We'll help identify the main risks before you buy.
Known engine and gearbox weak points.
Fault codes and symptoms to verify.
Inspection questions before negotiation.
This is buyer guidance, not a remote mechanical inspection or a guarantee. Always verify the car in person with diagnostics and service records.