What does code P0300 mean on a Ford and is it safe to drive?
P0300: Random/Multiple Cylinder Misfire Detected. Here's what it means on your Ford, 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 Ford
- 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 Ford, 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 Ford
Ford P0300 on the 5.4L Triton V8 (2004–2008) is infamous—spark plugs seize in the aluminum heads and break off when removed, leaving the plug tip in the combustion chamber. Use Ford's TSB procedure with a dedicated extractor kit and never remove plugs on a cold engine. On EcoBoost 3.5L F-150, P0300 can be caused by intercooler condensate washing oil off cylinder walls during cold, humid starts—Ford issued a calibration update to reduce this. On Mustang 5.0 Coyote, P0300 is uncommon but check for carbon buildup on GDI intake valves.
Most commonly affected models