Code
P0300
Ignition / Engine
Random / multiple cylinder misfire detected
The ECM detected misfires in multiple cylinders, usually from a shared ignition, fuel or air issue.
Advertisement
Most likely causes
- Spark plugs or ignition coils
- Vacuum leak or unmetered air
- Low fuel pressure or clogged injectors
- EGR fault
- Low compression
Symptoms you may notice
- Rough idle
- Shaking / hesitation
- Loss of power
- Flashing check engine light
Checks to run
- Read live misfire counts per cylinder
- Inspect plugs, coils and wiring
- Check fuel pressure and intake vacuum
- Compression test
Tools you may need
OBD-II scanner
Compression tester
Fuel pressure gauge
Multimeter
Always diagnose before replacing. Codes share symptoms; confirm the cause with measurements before buying parts.