For Shop Owners

P0304 FORD - Cylinder 4 Misfire Detected

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3 What does this mean?

Possible causes

  • Faulty spark plug 4
  • Clogged or faulty fuel injector 4
  • Faulty ignition coil 4
  • Fuel injector 4 harness is open or shorted
  • Fuel injector 4 circuit poor electrical connection
  • Ignition coil 4 harness is open or shorted
  • Ignition coil 4 circuit poor electrical connection
  • Insufficient cylinder 4 compression
  • Incorrect fuel pressure
  • Intake air leak
What does this mean?

Tech notes

The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 4. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes".





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