2008 GMC Acadia Running Lean on Bank 2, Rich on Bank 1: P0050, P0174, P0172 Diagnosis
My 2008 GMC Acadia is showing fault codes P0050, P0174, and P0172. The engine runs lean on bank 2 and rich on bank 1. I have already ruled out vacuum leaks and replaced all four oxygen sensors with OEM AC Delco parts. I also swapped injectors between banks with no improvement. Despite these efforts, the issue persists. Could this be related to a wiring circuit or sensor signal interference? I'm seeking advice on how to properly diagnose and resolve this imbalance in fuel mixture. Thanks for any insights. Randy
You replaced four oxygen sensors—be cautious, as a fault code does not always require sensor replacement. Always start by diagnosing the actual issue before assuming mixture problems. Check the OBD2 code description for P0050: it indicates a circuit-related issue (e.g., wiring or grounding). Did you inspect the circuit? Verify if there's a blown fuse or loose connection in the oxygen sensor circuit. Also, ensure that OEM AC Delco parts were used—avoid cheap aftermarket wires or connectors that may cause intermittent signals.