2000 Chevrolet 1500 Van P0171, P0172, P0430, and P0463 - Highway Hesitation After Long Storage
My 2000 Chevrolet 1500 Van is showing multiple OBD2 diagnostic codes: P0171 (Bank 1 Rich), P0172 (Bank 1 Lean), P0430 (Catalyst Efficiency - Bank 2), and P0463 (Fuel Level Sensor Issue). The vehicle runs smoothly at idle and in city driving, but experiences a noticeable hesitation when accelerating on the highway between 50-60 mph. I previously replaced several components including spark plugs, wires, distributor cap, rotor, ignition module, and ignition coils, as well as the crankshaft position sensor. After replacing the ECM (Engine Control Module), the vehicle started reliably and ran better initially. However, the hesitation persists under load. The van has been stored for approximately 6-9 months with no regular driving, which may have contributed to performance issues. I replaced a broken rod bearing at around 93,000 miles with a remanufactured unit having only about 12,000 miles on it. Despite these efforts, the codes remain active. I am seeking advice on how to resolve this issue, especially given the combination of oxygen sensor and catalytic converter-related faults. I have no scanner currently for real-time O2 sensor voltage or fuel trim readings, so any guidance on basic diagnostics (like fuel pressure test under KOEO conditions) would be greatly appreciated.
The P0171 and P0172 codes indicate Bank 1 is reporting both rich and lean air-fuel mixtures — this suggests a problem with the oxygen sensors or upstream air intake. P0430 is a catalytic converter efficiency code, typically associated with Bank 2; however, it's important to confirm whether the catalyst system is correctly mapped in your vehicle configuration. P0463 points to an issue with the fuel level sensor — this should be addressed after resolving O2 sensor faults. Do you have access to an OBD2 scanner to monitor live O2 sensor voltages on Bank 1? Also, check the fuel trim values for any abnormal readings. If no scanner is available, perform a fuel pressure test under KOEO (Key On, Engine Off) conditions and observe for any drops in pressure. After clearing all codes, take the vehicle for a drive to see if they return. Basic troubleshooting steps: verify fuel pressure, clean or replace the MAF sensor, and avoid using an oiled air filter — these are common causes of misfires and poor acceleration.