P0301 — Cylinder 1 Misfire Detected

P0301 means cylinder 1 specifically is misfiring. The fastest diagnosis is to swap the spark plug and ignition coil from cylinder 1 to another cylinder and see if the code follows.

Cost range: $30–$600. Severity: high. Safe to drive? Drive only if absolutely necessary. A flashing check engine light means stop driving — you're damaging the catalytic converter.

Most common causes of P0301

1. Bad spark plug on cyl 1 — Cheapest fix. Replace and clear code. ($10–$30)
2. Failing ignition coil on cyl 1 — Swap with cyl 2 — if the misfire moves, replace the coil. ($40–$200)
3. Faulty fuel injector on cyl 1 — Listen with a stethoscope for the click. ($200–$600)
4. Low compression on cyl 1 — Burnt valve or worn rings — major repair. ($1,500+)

Symptoms drivers report with P0301

• Engine vibration at idle
• Flashing check engine light
• Power loss