Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1997 GMC Savana Special, 1997 GMC Savana Camper Special, 1997 GMC Savana, 1997 Chevrolet RV Cutaway, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Visually inspect vacuum hoses. Check throttle body for possible cracked, broken or plugged vacuum block. Check engine for possible mechanical problem.