P0308

What does P0308 mean?

The computer has detected a misfire on cylinder 8.

Can I drive with P0308?

Based on this code and its usual severity, do not keep driving if the car is also shaking, losing power, overheating, smoking, or the check-engine light is flashing. Get it looked at before driving further. See Can I Drive It? for a quick read on your exact symptoms.

Common symptoms

• Check engine light, sometimes flashing
• Shaking or rough running
• Loss of power
• Hard starting
• A stumble under load

Possible causes

Possible causes include — not “the part is definitely bad”:

• Ignition on cylinder 8 (plug, coil)
• Fuel delivery to cylinder 8
• A vacuum leak or low compression on that cylinder

What P0308 does not prove

It identifies a misfire on that cylinder — it does not prove which part caused it. A coil, a plug, an injector, a vacuum leak, low compression, or wiring can all misfire the same cylinder.

What you can safely check

• Whether the check engine light is flashing — if so, ease off and get it looked at
• Whether the engine is shaking or down on power
• Whether it just had ignition or fuel work

What a shop may check

An example diagnostic direction, not a guaranteed procedure:

• Scan tool, freeze-frame and misfire-counter data
• Ignition (plugs, coils) on the affected cylinder
• Fuel delivery to that cylinder
• Compression and mechanical condition if ignition and fuel are good

What not to do

• Don’t ignore a flashing check engine light — an active misfire can wreck the catalytic converter
• Don’t just replace one coil or plug without confirming the misfire follows it

Generic OBD-II guidance — manufacturer-specific codes and causes vary by make, so always confirm against your vehicle. A code identifies a system or condition; it does not, on its own, prove which part has failed.