I am working on a 2006 Corvette GT2 spec'd car, so it's basically carbon fiber and roll bars. It's running a 6L LSx block with LS3 heads and C5R cam shaft from GM (25x/26x durations, <.610lift). It also runs on 110 leaded fuel so narrow bands are out of the question.
The company in which built this car has built another one using a 2002 C5 PCM, and that one works great. This car however is using a 2006 PCM, and I'm pulling my hair out. I can get it to idle at 950rpm, it goes cleanly through 8000rpm, but as soon as you let your foot off the gas pedal, the car will not catch the idle and will die. This is not something that happening with their other car.
I have been tuning for 8+years with HPTuners, and log over 40hrs a week on a chasis dyno all year, not to mention engine dyno's. I have over 30gigs of HPTuners files and data logs. This is the first time I have ever had this problem. I have tried adding and subtracted air via "airflow final minium", I have added and taken away spark from 6-30 degrees, and my AFR via the wide band is between 13.3-14.0.
I am including the data log and tune file. Look at time stamp 2min 34sec.