What P0300 means
More than one cylinder is misfiring, or the misfire moves around. A flashing check engine light with this code means raw fuel is reaching the catalytic converter — stop driving.
Common causes
- Worn spark plugs across the board
- Failing ignition coils
- Vacuum leak
- Low fuel pressure
- Carbon-fouled intake valves on a direct-injection engine
How it is usually fixed
- 1Replace spark plugs if past interval
- 2Check for cylinder-specific codes alongside this one
- 3Smoke-test for vacuum leaks
- 4Do a compression test if the misfire persists
Other common codes
- P0011 — Camshaft Position A – Timing Over-Advanced (Bank 1)
- P0030 — HO2S Heater Control Circuit (Bank 1, Sensor 1)
- P0101 — Mass Air Flow Circuit Range/Performance
- P0113 — Intake Air Temperature Sensor Circuit High
- P0118 — Engine Coolant Temperature Sensor Circuit High
- P0131 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
Code information is general guidance, not a diagnosis for a specific vehicle. Confirm with live data and manufacturer test procedures before replacing parts.