P0300 — Random/Multiple Cylinder Misfire Detected
High severityWhat it means
The engine control unit has detected misfires that are spread across several cylinders or cannot be pinned to a single one. Combustion is failing intermittently, which means unburned fuel can reach the exhaust and damage the catalytic converter over time.
Common symptoms
- Rough idle and noticeable engine shaking
- Hesitation or loss of power under acceleration
- Flashing or steady check engine light
- Increased fuel consumption
Likely causes
- Worn spark plugs or failing ignition coils
- Vacuum leaks in intake hoses or gaskets
- Low fuel pressure (weak pump, clogged filter or injectors)
- Low compression in one or more cylinders
- Contaminated or low-quality fuel
What to check first
- Inspect spark plugs and ignition coils for wear and age
- Check intake and vacuum hoses for leaks
- Watch misfire counters and fuel trims in live data
- Review the freeze-frame data to see RPM and load when the misfire occurred
Can you keep driving?
A flashing check engine light means an active misfire that can overheat the catalytic converter. Avoid driving any longer than necessary and have the engine checked promptly.
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