Cel P0171

[yosh]

I've been suffering from a reoccurring P0171 – System too lean
I first got the code after I filled up at Costco figuring it was a loose cap or bad gas. Went home, pulled the code and checked the manual.

Loose air intake hose or duct
Incorrect fuel line pressure
Obstruction in injector
Heated O2 sensor malfunction
MAF sensor malfunction
ECT sensor malfunction

I checked for oil in the intake, there was very little. Visually inspected the MAF, but I could barely see the wire. I ran some fuel system cleaner. I checked for loose lines. I have sufficient fuel upgrades for stock boost. One thing I just noticed today is the code usually pops up within a few minutes of turning on the A/C. It has been getting warmer here and I’ve started using the A/C. I may have turned it on after filling gas. The car drives perfectly fine. Any help?

[BadChicken]

usually indicates a faulty MAF sensor or loose vacuum line
hope this helps

[yosh]

Thanks, I'll check the lines again. Hopefully I won't have to replace the MAF.

[2wickedtoyz]

i know this thread is old but i figured i'd revive it.

i changed out my o2 sensor, cleaned out my maf, my intake manifold is spotless.

my problem was my fpr...or that was one of them the other i noticed was my o rings were worn. hope this helps some one in the future

[yosh]

My code went away after coming on maybe five times. Not really sure what it was. The only thing I could think of was maybe a stuck injector and the fuel system cleaner worked.