2007 Chevrolet Equinox P0171 Code: Persistent Check Engine Light and Hard Start Issue
I own a 2007 Chevrolet Equinox with 175,000 miles that has been running smoothly but now shows a persistent P0171 code and a constantly illuminated check engine light. I've already replaced the MAF sensor, PCV valve, intake gasket, spark plugs, and performed two smoke tests—none of which detected any issues. Fuel pressure is consistently reading 45 psi, and O2 sensors are within specifications. I’ve even replaced the ECU with a certified rebuilt unit. The vehicle runs well, accelerates smoothly up to 70+ mph, and performs reliably under normal conditions. However, it exhibits a recurring issue: it will not start on the first key turn—only after the second attempt does it fire up successfully. This behavior is consistent across multiple cold starts. I’ve tried various troubleshooting steps but am now at a loss. Has anyone else experienced this specific combination of P0171 code and intermittent hard-start symptoms? Any insights or diagnostics would be greatly appreciated.
If all components were functioning properly, the vehicle shouldn't show a fault code. This suggests either a defective component was not properly tested or an overlooked issue exists. The symptom you're describing—difficulty starting on the first key turn—is consistent with a cold-start problem. Was fuel pressure checked during KOEO (key-on engine-off) 3-second prime and while cranking? If the engine fails to start cold, it may keep cranking until the second attempt is made.