P0306 serious

Cylinder 6 Misfire Detected

What does P0306 mean?

The P0306 code means the vehicle's onboard diagnostic system has detected: Cylinder 6 Misfire Detected. This is a serious severity code.

Common Symptoms

  • Rough idle
  • Vibration
  • Check Engine Light
  • Loss of power

Probable Causes (Ranked by Likelihood)

  • Faulty spark plug on cylinder 6 Very High
  • Failed ignition coil on cylinder 6 High
  • Clogged fuel injector on cylinder 6 High
  • Low compression on cylinder 6 Moderate

Step-by-Step Diagnostic Procedure

  1. Swap cylinder 6 coil with an adjacent cylinder and recheck codes.

  2. Inspect and replace spark plug on cylinder 6.

  3. Test injector balance and compression as needed.

Frequently Asked Questions

On a V6, is cylinder 6 easy to access?

On transversely mounted V6 engines (common in front-wheel-drive vehicles), the rear bank (cylinders 4, 5, 6) can be difficult to access without removing the intake manifold. Factor this into repair cost estimates.

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