my motor stumbles bad in the morning and throws the code
OBDII Error Summary related to Fuel Mixture
Code Detected Condition Trouble Area
P0171 System too Lean (Bank 1)

When air fuel ratio feedback is stable after engine warm up, fuel trim is considerably in error on the RICH side (2 trip detection logic)

* Air Induction System Leak
* Injector Blockage
* Mass Air Flow Meter
* Engine Coolant Temperature Sensor
* Fuel Pressure
* Gas Leakage from the Exhaust System
* Open or Short in the Oxygen Sensor or associated wiring
* Oxygen Sensor Defective
* Engine Control Unit

all of this happened after the first cold night back east here. it got in the 40's and the next morning i got to wake up to stumbling. anyone had this problem? i look over this list of potentials and dont know where to start. it happend after a cold morn but nothing here looks obvious to me. the fuel mileage is really about the same as it has been. where would you start in looking for a problem?
thanks

the is a gm preliminary info on this, they are saying there is a vacuum leak around the intake gasket seals.They say they leak at the botton of the seal, making it hard to detect. There is an updated part number 89017589 for a better seal. The pi also says to check for manifold warpage over 3mm.
HTH

If you want a copy of the document, just e-mail me.

looks like i am moving to gaskets. did an O2 at bank one. this morn it pulled 171, 174, and 101. left bank 1, bank 2, and maf. so it would make sence the gasket is the problem. so i am going to look into that further.
thanks

dump water on each side of the intake while it is running rough if the way it runs changes then the gaskets are the problem. MY .02$:grinpimp:

definatly check the intake gaskets i change tons at work every week, very common.