P0301 — Cylinder 1 Misfire Detected
Drivable short-term, but fix now to avoid damage.
What P0301 means
P0301 means the engine computer detected that cylinder number 1 is misfiring. That cylinder isn't burning its air-fuel mixture properly, so it loses power and the engine runs unevenly. Because it points to one specific cylinder, the cause is usually a worn part on that cylinder like its spark plug, coil, or injector.
Common symptoms
- Check engine light on or flashing
- Noticeable rough idle and vibration
- Power loss, especially under load
- Engine hesitates or stumbles
- Possible smell of raw fuel
Common causes
- Worn or fouled spark plug on cylinder 1
- Failing ignition coil on cylinder 1
- Clogged or leaking fuel injector
- Bad spark plug wire or boot
- Vacuum leak near that cylinder
- Low compression in cylinder 1
Typical repair cost
$80 – $450
Varies by vehicle and root cause.
Frequently asked questions
Can I drive with P0301?
Only short distances and gently. If the engine light is flashing, stop driving immediately to protect the catalytic converter and have the car towed.
How much does it cost to fix a P0301?
Often inexpensive: a single spark plug or coil for cylinder 1 typically runs $80-$300 with labor. A fuel injector or compression-related repair can cost more.
Is a P0301 serious?
It can be. Even one misfiring cylinder can overheat and damage the catalytic converter, so it's best to fix it soon rather than ignore it.
Which cylinder is cylinder 1?
Cylinder 1 is the first cylinder in your engine's firing order, and its location varies by engine. A repair manual or technician can identify it, but the code already tells you exactly where to focus.