P0308 — Cylinder 8 Misfire Detected
Category: Powertrain Severity: High
Updated:
DTC code P0308 means: Cylinder 8 Misfire Detected. It falls under the "Powertrain" category, with an estimated severity of High. Common causes include faulty spark plug or coil (cylinder 8), faulty fuel injector (cylinder 8) and vacuum or intake leak; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Faulty spark plug or coil (cylinder 8)
- Faulty fuel injector (cylinder 8)
- Vacuum or intake leak
- Low compression on that cylinder
Symptoms
- Rough idle or engine shake
- Check engine light flashing (risk to the catalytic converter)
- Power loss on acceleration
- Increased fuel consumption
How to diagnose it step by step
- Swap the cylinder 8 coil.
- If the misfire follows it, replace it.
- If not, swap the spark plug.
- Check the injector and compression if it persists.
How to fix it
Check the spark plug, ignition coil and injector for cylinder 8 first (swap parts between cylinders to confirm); if the misfire follows the part, replace it. A flashing check engine light means stop and get it checked immediately — a sustained misfire can destroy the catalytic converter.
Estimated repair cost
$10–400 depending on the part.
Frequently asked questions
What does DTC code P0308 mean?
Cylinder 8 Misfire Detected.
Is code P0308 serious?
Severity High. Have it checked as soon as possible, especially if it affects safety or the catalytic converter.
Can I keep driving with code P0308?
Avoid it if the light is flashing; with a steady light, only as needed.
Related codes
P0307 P0306 P0305 P0304 P0303 P0302 P0301 P0300 P0316 P0320
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