Diagnostic Aids
WARNING: This page is about a different car, the 1997 GMC Savana, 1997 Chevrolet Chevy Van, and 1997 Chevrolet Chevy Express. 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 P0175 setting. Also, an extreme rich condition that may cause DTC P0175 to set may result in P0300 setting due to misfire at idle. If cause for DTC P0175 cannot be determined and DTC P0300 is also set, go to DTC P0300 .