P0300
Random / Multiple Cylinder Misfire Detected
What P0300 means
The engine control module detected misfires it could not pin to one cylinder. More than one cylinder is failing to burn its charge properly, or the cause is something all cylinders share, like fuel pressure or a vacuum leak.
Symptoms you may notice
- Rough or shaking idle
- Loss of power under acceleration
- Flashing check engine light
- Poor fuel economy
Common causes, cheapest first
- Worn spark plugs across the set
- Failing ignition coils
- Vacuum leak downstream of the mass airflow sensor
- Low fuel pressure or a failing fuel pump
- Clogged fuel injectors
- Low compression from worn rings or valves
What to do next
- Confirm the code with your own scan tool, or have it read free at a chain parts store.
- Decode your VIN so you know your exact engine and build date.
- Work down the causes above from cheapest to most expensive.
- Search NHTSA for a recall or service bulletin covering this symptom on your vehicle.
- Read the ignition buying guide before ordering.
P0300 is a generic OBD-II code, standardized across every make and model sold in the US from 1996 onward. The meaning is the same on any vehicle; the specific part and its location are not.
Parts commonly needed for P0300
These go to Amazon. We earn a commission if you buy, at no extra cost to you — see our affiliate disclosure. Which one you actually need depends on diagnosis — read the note above first.
Confirm fitment against your VIN on the listing page before ordering. A part that matches your year and model can still be wrong for your build date or engine code.