Engine Misfire Detected on Startup (First 1000 Revolutions)
The misfire monitor detected misfires during the first 1000 revolutions after startup but the engine then settled. Often caused by fouled spark plugs that warm up clean, weak ignition coils, or a borderline cold-start fuel mixture.
Affected components
- Spark plug
- Ignition coil
- Fuel injector
Common causes
- High likelihood: Spark plugs fouled when cold
- Medium likelihood: Ignition coil weak below operating temperature
- Medium likelihood: Cold-start mixture too lean (fuel pressure, leaking injectors at rest)
Possible symptoms
- Check engine light on or flashing
- Rough idle and uneven running
- Power loss, hesitation under acceleration
- Increased fuel consumption
- Possible smell of unburned fuel from exhaust
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.