P0171

[pfmeeks]

04 Bonneville 3.8 n/a motor ive only owned it about a week and it was running very rough. I found out the MAF connector was bad and the upstream O2 sensor was bad so I replaced both. She drove it past few days, it has a slight miss at idle mostly, but runs much much better. Today.. now its popping up the code P0171 which is lean on bank 1.

Ive used starting fluid and sprayed all around the intake manifold and no signs of vac leak. I checked with a vacuum gauge and its showing steady 20in at idle which I guess is good ?

Ive checked the fuel pressure with a gauge and at idle it shows 45psi

Any other ideas ??

[Jfridge92]

I just got through this issue myself. Here's my thread with a lot of good troubleshooting information for the code.

http://www.pontiacbonnevilleclub.com/fo ... t=%20p0171
It turned out that my injector o-rings weren't sealing where the injectors seat into the LIM, and replacing them fixed my issue. Shoot some carb cleaner at the injectors really good and see if the Idle changes at all. Also, the EGR tube that connects to the LIM likes to crack and cause a vacuum leak that's hard to detect with carb cleaner.

[pfmeeks]

Thanks Jfridge. Its been a pain trying to figure it out.

[Jfridge92]

Yeah that code has put a lot of us through more trouble than we care to admit haha. The EGR tube is probably the most common cause of that code, and is also one of the hardest spots to diagnose unless you have a smoke machine, otherwise short of pulling the TB out of the way, it's almost impossible to check with carb cleaner. Hopefully you're able to track it down soon though.

[pfmeeks]

I sprayed all around the injectors, intake, vac hoses, pvc, and didn't make any difference. I guess its time to pull the egr tube.. :(