Engine Controls - Tests W/Codes - 4.9L: Summary

If no current or hard fault codes (or only pass codes) are present, driveability symptoms exist or intermittent codes exist, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

NOTE: References to vehicles equipped with Multiport Fuel Injection (MFI) is also referred to as Port Fuel Injection (PFI).