P0301 Code: Cylinder 1 Misfire Detected
🟠 Moderate severity · drivable
If the light is flashing, stop immediately. A steady light means you can usually drive a short distance, but get it fixed to avoid converter damage.
What P0301 means
Cylinder 1 is misfiring — it's not producing its share of power. Unlike P0300 (random misfire), P0301 points to a specific cylinder, which usually means a part specific to that cylinder is at fault.
Symptoms
- Check engine light on (flashing if severe)
- Rough idle or engine shaking
- Loss of power
- Poor fuel economy
Common causes
- most common: Bad spark plug on cylinder 1
- most common: Failing ignition coil or plug wire for cylinder 1
- common: Clogged or leaking fuel injector on cylinder 1
- less common: Vacuum leak affecting that cylinder
- less common: Low compression in cylinder 1
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the cylinder 1 spark plug | Yes | $10–50 |
| Replace the cylinder 1 ignition coil (or swap it to confirm) | Yes | $50–200 |
| Clean or replace the cylinder 1 fuel injector | Mechanic | $100–300 |
| Run a compression test on cylinder 1 | Mechanic | $100–200 |
Frequently asked questions
Where is cylinder 1?
Cylinder 1 is the cylinder closest to the front of the engine on most vehicles, but the exact location varies by make. Your vehicle's firing-order diagram will confirm it.
Can I drive with a P0301 code?
Short distances only if the light is steady. A flashing light means stop and get towed to protect the catalytic converter.
Is P0301 usually an expensive fix?
No — it's often just a $10–$50 spark plug or a $50–$200 ignition coil. It gets expensive only if compression or the injector is the problem.
Related codes
P0300
P0300 Code: Random/Multiple Cylinder Misfire Detected
P0302P0302 Code: Cylinder 2 Misfire Detected
P0171P0171 Code: System Too Lean (Bank 1)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.