OBD-II code guide

P0306 Cylinder 6 Misfire Detected

P0306 means the engine computer detected a misfire on cylinder 6.

What it means

Cylinder 6 is misfiring often enough for the computer to flag a fault.

Common symptoms

  • Engine shaking
  • Rough idle
  • Poor power
  • Flashing check engine light
  • Fuel smell

Likely causes

  • Ignition coil fault
  • Worn spark plug
  • Injector issue
  • Compression problem
  • Vacuum leak

First checks

  • Stop hard driving if the light flashes.
  • Confirm cylinder numbering for the engine.
  • Swap-test only when safe and appropriate.
  • Check for related fuel trim or coolant loss clues.