System Too Lean
WARNING: This page does not describe the selected car, but rather 25 other vehicles, including the 1992 Oldsmobile Bravada, 1992 GMC Vandura Special, 1992 GMC Vandura, 1992 GMC Value Van, and 1992 GMC Sonoma. However, it is still accessible from the selected car via links, so may be relevant.
If air/fuel ratio is too lean, the idle speed may be either too high (check for vacuum leaks) or too low. Engine speed may vary and disconnecting the IAC may not help. Scan and/or digital voltmeter (10 megohm) will read an oxygen sensor output less than 300 mv (.3 volt). Check for low fuel pressure or water in the fuel.