I'm going to ask for a copy of the tune tomorrow, its definetly a closed loop issue. The o2's are working, I was able to watch the Live Data on the Tech 2 at work, I can see them oscillating and all 4 are working as there supposed to.

Its seems worse with a load in gear (a/c on) it "hunts" horribly, the desired idle is set to 900, but wont go any more than 600-700 and stalls without feathering the throttle.

Fuel pressure is about 58-62 PSI

I've had it back and forth 3 times now after the initial tune to correct the issues, but I don't think getting better, I have a feeling this might be too much for them get right.

I appreciate all the help guys, Ill update tomorrow if I can get the tune/log file.

 

Just a suggestion, but with my first tune i had similar issues. After many retunes i went with a diff tuner and come to find out it was a dirty throttle body after cleaned it was good to go after a couple of new adjustments. As you said you are a gm tech so im sure its clean but just a thought.