Section 4 (Engine Controls Tests W/Codes 3.8L): Summary
WARNING: This page is about a different car, the 1997 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.
If no hard fault codes are present, driveability symptoms exist or intermittent DTC(s) exist, proceed to the TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.