P0300: Random/Multiple Cylinder Misfire Detected
The engine computer detected misfires in more than one cylinder, or misfires it can't pin to a single cylinder. Something is affecting the whole engine rather than one cylinder.
Green, yellow, red: three ways P0300 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Light is steady, the engine runs nearly normal, and the miss only shows up on a cold start or in damp weather.
Schedule a repair
Steady light with a noticeable shake or hesitation. Get it diagnosed soon. Unburned fuel is building heat in the catalytic converter.
Stop and get help
Light is flashing, the engine is bucking, or you smell raw fuel. Slow down and stop driving as soon as you can. A severe misfire can melt the catalytic converter within miles.
Symptoms you might notice
- Rough idle or shaking
- Hesitation or stumbling when accelerating
- Check engine light, possibly flashing
- Worse fuel economy
Common causes, cheapest first
- Worn spark plugs
- Vacuum leak
- Low fuel pressure or a weak fuel pump
- Dirty MAF sensor
- EGR valve stuck open
- Low compression or a timing chain problem
What you can check before calling
- Note if the light is steady or flashing
- Check when spark plugs were last changed
- Listen for a hiss from a vacuum leak at idle
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Want the full story? Read our guide: P0300–P0308 misfire codes, explained.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More misfire & ignition codes
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0300 mean?
P0300 means "Random/Multiple Cylinder Misfire Detected". The engine computer detected misfires in more than one cylinder, or misfires it can't pin to a single cylinder. Something is affecting the whole engine rather than one cylinder.
Can I drive with code P0300?
It depends on what the vehicle is doing. Green: Light is steady, the engine runs nearly normal, and the miss only shows up on a cold start or in damp weather. Yellow: Steady light with a noticeable shake or hesitation. Get it diagnosed soon. Unburned fuel is building heat in the catalytic converter. Red: Light is flashing, the engine is bucking, or you smell raw fuel. Slow down and stop driving as soon as you can. A severe misfire can melt the catalytic converter within miles.
What causes P0300?
The most common causes are: worn spark plugs; vacuum leak; low fuel pressure or a weak fuel pump.
Is P0300 a serious code?
It can be. Light is flashing, the engine is bucking, or you smell raw fuel. Slow down and stop driving as soon as you can. A severe misfire can melt the catalytic converter within miles.
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