2002 Chevrolet Express Van P0171 and P0174 After Fuel Pump Replacement
My 2002 Chevrolet Express van experienced a fuel pump failure. I replaced both the fuel pump and filter, and the vehicle runs smoothly afterward. However, after approximately 100 miles of driving, the onboard diagnostic system displays fault codes P0171 (Rich Mix Bank 1) and P0174 (Rich Mix Bank 2). I have reset the codes multiple times, but they reappear within a few miles of driving. The issue seems to persist despite proper fuel pump installation and operation.
No diagnostic trouble codes were present prior to the fuel pump replacement. It's recommended to check fuel pressure using a gauge, as low or inconsistent pressure can cause misfires and rich air-fuel mixtures. Additionally, inspect for vacuum leaks, which may contribute to incorrect air-fuel ratios and trigger P0171 and P0或P0174 codes.