← Back to list

1997 Ford Explorer 4.0L Engine P0303 Misfire: Diagnosis & Solutions

Model: 1997 Ford Explorer Fault Code: P0303 Posted: 2017-02-24 16:00

Vehicle: 1997 Ford Explorer 4.0L V6 Fault Code: P0303 - Cylinder 3 Misfire Detected Symptoms: - Engine runs on only five cylinders - Previous troubleshooting steps include replacing spark plugs and fuel injectors - Ignition wires have been verified as functional Current Status: - Spark at cylinder #3 confirmed via plug inspection - After test drive, the check engine light reactivated - New diagnostic codes show misfires in cylinders 4 and 6, not just cylinder 3 - Vacuum and compression tests indicate no mechanical issues Question: What is the next step to diagnose and resolve this multi-cylinder misfire issue? Please advise on fuel system checks, ignition components, or sensor diagnostics.

Related fault codes
P0303
Comments (3)
Anonymous 2017-02-24 16:12

The only fault code reported is P0303. Cylinder #3 is located on the passenger side rear bank. Confirm if there's spark at the plug. Use a noid light to verify fuel injector pulsing. Check the appearance of the spark plug—wet, black, or dry/tan? Also consider compression and vacuum levels as potential diagnostic areas.

Anonymous 2017-03-02 16:42

I tested cylinder #3 for spark — confirmed spark present. After a test drive, the check engine light turned on again. Re-scanning revealed new misfire codes: cylinders #4 and #6. Vacuum and compression tests showed no issues. This suggests the problem may be broader than just one cylinder. What should I do next? Any guidance appreciated?

Anonymous 2017-03-03 09:32

A diagnostic scanner would help quickly identify fuel trim values, oxygen sensor voltages, and other parameters. Confirm that fuel injectors are pulsing properly—check electrical connections for tightness and corrosion. Examine spark plugs #4 and #6: are they wet and black or dry and tan? Also consider checking fuel pressure and its stability under load (leak-down test).