P0301
Moderate severityCylinder 1 Misfire Detected
You can drive short distances, but fix it soon — a persistent misfire dumps unburned fuel into the exhaust and can damage your catalytic converter. If your check engine light is flashing, stop driving.
Stop driving if: the check engine light is flashing, or the car starts running noticeably worse
What does the P0301 code mean?
The P0301 code means cylinder 1 specifically is misfiring — it is not firing (burning fuel) the way it should. Because the code names the exact cylinder, diagnosis is easier: you know precisely where to look.
A misfire usually comes down to one of three things at that cylinder: spark (plug or coil), fuel (injector), or compression. If several cylinders misfire at once, you may also see P0300.
Can you keep driving with a P0301 code?
Yes, for short distances — but don’t ignore it. A steady misfire can overheat and ruin the catalytic converter, and the car may run rough or lose power. Get it fixed soon. If the check engine light is flashing, the misfire is active and damaging; pull over and stop driving.
What causes a P0301 code?
Listed in the order most shops would check them — cheapest and most likely first, not as statistical odds. The real cause varies by year, make, model and engine.
- Clogged or leaking fuel injector (cylinder 1)Check 1st
- Vacuum leak or low compressionCheck 2nd
- Failing ignition coil (cylinder 1)Check 3rd
- Worn or fouled spark plug (cylinder 1)Check last
How to diagnose a P0301 (check these first)
- Inspect the spark plug for cylinder 1 — cheap and often the culprit.
- Swap the ignition coil with a neighboring cylinder. If the misfire follows the coil, you found it.
- Check the fuel injector for cylinder 1.
- If it persists, do a compression test to rule out a mechanical issue.
P0301 repair cost
Typical US ranges including parts and labor (varies by vehicle):
Costs vary a lot by vehicle and region. These are typical US ranges including parts and labor — treat them as a ballpark for the conversation with your shop, not a quote.
| Spark plug | – |
| Ignition coil | 0 – 0 |
| Fuel injector | 0 – 0 |
Tools & parts that help
A OBD-II scanner confirms the exact cylinder and any related codes before you buy parts. A coil and plug for one cylinder are inexpensive fixes.
See top-rated OBD-II scanners ›As an Amazon Associate I earn from qualifying purchases. This costs you nothing extra and never changes what we recommend.
P0301 — Frequently asked questions
Is it safe to drive with a P0301 code?
For short distances, yes, but fix it soon. If the check engine light is flashing, stop driving – an active misfire can destroy the catalytic converter.
How do I know if it’s the coil or the spark plug?
Swap the ignition coil to a different cylinder. If the misfire code follows the coil to the new cylinder, the coil is bad; if it stays, suspect the plug.
What’s the difference between P0300 and P0301?
P0300 is a random or multiple-cylinder misfire, while P030{num} points to one specific cylinder (number {num}).
How much does it cost to fix a P0301?
Often – for a spark plug or 0-0 for an ignition coil, depending on your vehicle.
Related codes
General guidance based on the standard SAE definition of the P0301 code. A real diagnosis depends on your make, model, year, engine and other symptoms. This is not a substitute for a professional inspection — when in doubt, have a technician confirm the cause before replacing expensive parts.