Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, 2002 Chevrolet RV Cutaway, and 2002 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
When the PCM is in backup fuel: long crank times, fast idle, and poor performance conditions will exist. Check for a good connection at the crankshaft position sensor and at the PCM. Many intermittent problems are caused by poor electrical connections or wiring. When attempting to diagnose an intermittent problem, always begin by trying to reproduce the conditions under which the failure occurs. This usually involves raising the engine to a higher temperature or operating the engine near the RPM where the problem occurs. Since heat and vibration are often the cause of the intermittent, this may bring out the failure.