P0304 Cylinder 4 Misfire Detected

Powertrain Severity: High Generic OBD-II

Cylinder 4 is not firing correctly.

Common causes

  • Worn spark plug in cylinder 4
  • Faulty ignition coil
  • Leaking or clogged injector
  • Vacuum leak near this cylinder
  • Low compression

Symptoms

  • Check engine light (may flash)
  • Rough idle
  • Shaking
  • Loss of power

What to check

  1. Swap the coil with another cylinder and see if the misfire follows
  2. Inspect the spark plug
  3. Check injector operation
  4. Do a compression test

Manufacturers may add their own detail to generic codes. If your vehicle shows a different description for P0304, follow the service information for that make and model.

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