P0300: Random/Multiple Cylinder Misfire Detected
Severity: High
What it means
The engine computer sees misfires in more than one cylinder, or can't tell which cylinder is misfiring.
Common symptoms
- Rough idle or shaking
- Flashing check engine light
- Loss of power
- Poor fuel economy
Common causes
- Worn spark plugs or ignition coils
- Vacuum leak
- Low fuel pressure or clogged injectors
- Low engine compression
What to check first
- Check when the plugs were last replaced
- Listen for hissing near the intake (vacuum leak)
- Look for cylinder-specific codes (P0301–P0308) stored with it
Causes vary by vehicle. Confirm with testing before replacing parts.
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