P0171 OBD2 Fault Code for 2007 Chevrolet C2: Diagnosis and Fixes

Model: Chevy C2 2007 Fault Code: P0171 Posted: 2016-07-28 23:30

I need help — the P0171 diagnostic code appears on my 2007 Chevrolet C2. I have already replaced the oxygen sensors and the IAC valve, but the P0171 code persists. What could be causing this issue? The vehicle runs roughly and has poor fuel efficiency. Any suggestions for further troubleshooting or possible underlying causes?