P0300: Random/Multiple Cylinder Misfire Detected

What does P0300 mean?

The engine computer has detected misfires that are not limited to one cylinder. Because several cylinders are affected, the root cause is usually something shared: fuel pressure, a vacuum leak, ignition parts that are all worn, or a sensor feeding bad data.

Generic OBD-II definition: Random/Multiple Cylinder Misfire Detected. Confirm applicability in your vehicle service information.

Common causes

• Worn spark plugs across several cylinders
• Low fuel pressure (weak pump or clogged filter)
• Large vacuum leak
• Faulty MAF sensor reading
• Contaminated or low-quality fuel

Symptoms

• Rough idle or shaking
• Hesitation or stumble when accelerating
• Flashing check engine light under load
• Reduced fuel economy

Can I keep driving with P0300?

Severity: High Stop or minimize driving and get it looked at right away.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Check for other stored codes first (lean codes often point to the cause)
• Inspect for vacuum leaks
• Test fuel pressure
• Replace spark plugs if due