I have a 2006 Chevy Colorado 2.8l with 55,000 miles and I have been getting the code p0171. In the past 6 months I have had the throttle body replaced, and an o2 sensor installed. While at the dealer they said that it needs a thermostat, because when accelerating the temp gage will drop to ¼ and will return to the ½ mark after up to normal rpm. The dealer told me that the thermostat is not covered under my extended warranted. So I just wanted to know if the bad thermostat could make the code come up that it is running to lean. I have also cleaned the mass air sensor, and have checked the vent hose from the valve cover to the intake.
2006 chevy colorado extended cab LS z85
4:10 gears g 80 locker
5 spd standard
31x10.5x15 Firestone Destination mt
Dezee tool box
spray in bed liner