What does code P0300 mean on a Pontiac and is it safe to drive?
P0300: Random/Multiple Cylinder Misfire Detected. Here's what it means on your Pontiac, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
The PCM has detected misfires across multiple cylinders. This can cause damage to the catalytic converter if driven for long.
Common causes for your Pontiac
- Worn spark plugs or ignition coils
- Clogged or bad fuel injectors
- Low compression
- Vacuum leak, bad MAF, or fuel delivery issue
Symptoms
- Check Engine Light (often flashing under load)
- Rough idle, shaking, loss of power
- Possible smell of unburned fuel
Typical fixes
- Replace spark plugs and coils as needed
- Clean or replace fuel injectors
- Fix vacuum/fuel issues
- Compression test if no obvious cause
Repair cost range
For a Pontiac, repairs for P0300 often fall between $150 and $1200, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Pontiac
Pontiac G6 3.5L and 3.9L V6 (LX9/LZ4) engines have a known Delphi ignition coil failure pattern—individual coil-on-plug units fail at 80k–100k miles, often causing P0300 before isolating to a specific cylinder P030X code. Replace all six coils and spark plugs as a set. On G8 6.0L LS2 V8, P0300 is uncommon and usually indicates a spark plug issue—use OEM AC Delco iridium plugs only; aftermarket plugs in the LS2 often cause misfire. Pontiac Vibe (Toyota drivetrain) should follow Toyota P0300 diagnosis.
Most commonly affected models