The Lemon IndexCylinder 8 is not firing properly, so the engine runs rough and loses some power.
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
Spark plug or ignition coil on cylinder 8. Then: fuel injector on cylinder 8; vacuum leak near that cylinder.
Owners named P0308 in 12 complaints to the U.S. government, most often on the GMC Sierra.
Cars owners report it on
Complaints that name P0308, by model. Raw counts, not a failure rate: popular models get more complaints.
Years owners report it on most: 2019 GMC Sierra
The details
What P0308 means
Cylinder 8 is not firing properly, so the engine runs rough and loses some power. A flashing check engine light means the misfire is serious enough to damage the catalytic converter, so slow down and get it checked right away.
Can I drive with P0308?
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
67% of the owner complaints that name P0308 also say the car shakes, runs rough or misfires. A complaint can describe more than one problem, so this doesn't prove the code caused it.
Common causes of P0308
- Spark plug or ignition coil on cylinder 8
- Fuel injector on cylinder 8
- Vacuum leak near that cylinder
- Low compression (valve or piston ring problem)
A shop should confirm the cause with a scan and tests before replacing parts.
What owners describe
- Shakes, runs rough or misfires: 67% of complaints
- Loses power or goes into limp mode: 50% of complaints
- Stalls or shuts off: 25% of complaints
- Rattles or knocks: 17% of complaints
Share of complaints naming the code whose text also mentions each problem.
Model years that report P0308 most
2019 GMC Sierra (2).
Related codes
P0307 P0309 P0306 P0305 P0304 P0303 P0302 P0301
Quick answers
What does P0308 mean?
Cylinder 8 Misfire Detected. Cylinder 8 is not firing properly, so the engine runs rough and loses some power. A flashing check engine light means the misfire is serious enough to damage the catalytic converter, so slow down and get it checked right away.
Can I drive with P0308?
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
What causes P0308?
Spark plug or ignition coil on cylinder 8; Fuel injector on cylinder 8; Vacuum leak near that cylinder; Low compression (valve or piston ring problem).
Counts: NHTSA owner complaints whose text names P0308. A complaint is an owner's report, not a diagnosis. Meanings: the standard SAE J2012 definitions in our own words; manufacturer codes only where verified for that make. General information, not repair advice for your car.