Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
A slow, unstable, or fast idle may be caused by a non-lAC system problem that cannot be overcome by the IAC valve. Out of control range, IAC Tech I "Scan" tool counts will be above 60 if idle is too low, and zero counts if idle is too high The following checks should be made to repair a non-lAC system problem.