P0301: Cylinder 1 Misfire Detected
P0301 is a specific cylinder misfire on cylinder 1. Codes P0302–P0312 follow the same pattern for other cylinders.
Severity: serious · System: Powertrain · Safe to drive: no — get it checked. Get it checked within a week. Extended driving risks catalytic converter damage.
Symptoms
- Rough running
- Reduced power
- Poor fuel economy
- Flashing CEL under load
Common causes
- Bad spark plug on cyl 1
- Failed coil on cyl 1
- Injector fault
- Low compression
Fair repair prices
| Single spark plug + coil (cyl 1) | $90–$280 |
|---|---|
| Injector replacement (single) | $250–$600 |
| Compression diagnosis | $120–$200 |
Ranges are US market averages (parts and labor). If your shop's quote is above the high end, ask for a line-item breakdown or run it through the invoice checker.
Other codes
- P0300 — Random / Multiple Cylinder Misfire Detected
- P0420 — Catalyst System Efficiency Below Threshold (Bank 1)
- P0430 — Catalyst System Efficiency Below Threshold (Bank 2)
- P0171 — System Too Lean (Bank 1)
- P0174 — System Too Lean (Bank 2)
- P0442 — Evaporative Emission Control System Leak (Small)
- P0455 — Evaporative Emission Control System Leak (Large)
- P0128 — Coolant Temperature Below Thermostat Regulating Temperature