I have a 2006 4200 trailblazer engine that is turbocharged, Its draw through MAF. The problem I am having is on decel the afr drops well in to the 9s and the motor stumbles and stalls. There appears to be limited tables available for this PCM. I have scaled all of DFCO tables up and down, lowered Min PW ans Short pule adder with no positive results. Fuel trims will be close 3 to 5 % cruising in a particular MAF cell and during decel the same cell will be -30%. I am tuning with a wide band but did not have it on during these logs.
Make sure that all of your injector characterization data is correct. If all of that is good, then you'll be very limited on your options. You can always open up the window for DFCO...increase it from the current 1200 rpm up to 1600 or so...