Ok here goes. I have a 2003 monte Carlo 3.8l v6 showing a code p0171. I've had two mechanics check this out and both came up empty handed. We have replaced bank one 02 sensor, maf sensor, ambient air temp sensor, iac valve, checked for vacuum leaks, throttle position sensor, and new intake gasket and cover. The mechanics said the fuel pump is running fine and they cant find any vacuum leaks anywhere. The car stalls everytime I start it for about four times then it stays running. I have to hold the gas petal down to keep the engine running during starting. That is really the only symptom other than the mil coming on. What else can it be?

 

Welcome to the forum. I wouldn't have done all that on a single bank lean condition. If it's not the O2 sensor and vacuum leaks, suspect the clogged fuel injectors on that bank. It'd be interesting to know what the fuel trim values look like on the other, supposedly working, bank as well. The injectors there might be clogged but just not enough to trigger a trouble code.

 

I had the same thought. Do you know if either of the mechanics diagnosed the FI wiring and connectors to determine if there is a loose/dirty/bad connection at any of the injectors...or did they just (what it sounds like) throw parts at it in hopes of solving the problem?

 

theres a TSB for these symptoms involving cleaning injectors

 

The car only stalls when the engine is hot. Cold starts are ok, they flutter a little bit but the car remains running. Also, this car is now running on its FOURTH catalytic converter because the dealership was just fixing the symptom and not the real cause which is what I am chasing. I am going to get my injectors cleaned soon and see if that helps. Thanks

 

Keep us updated if you find the issue. I'm sure theres others out there that can benefit from your story and repairs..thanks!