Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 1997 GMC Yukon, 1997 GMC Suburban, 1997 GMC Pickup, 1997 GMC Cab & Chassis, and 1997 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
If problem can not be isolated during diagnostic procedures, monitor LT fuel trim value while operating vehicle under various load conditions. A condition that causes DTC P0300 may also result in DTC P0172 setting. Also, an extreme rich condition that may cause DTC P0172 to set may result in P0300 setting due to misfire at idle. If cause for DTC P0172 can not be determined and DTC P0300 is also set, go to DTC P0300 .