Thanks Shaun. i had the crankshaft relearn done this morning by my local shop. They had not heard of it before for Gm products but went ahead and did it after some research. They could not get it to set a code on the test drive after the relearn. I just brought it home and I would say it seems to run a little differently, not better or worse just different.
More data. The misfires were on cylinders 1,3,5, and 8. Two of the cylinders, one from each bank had like 40K misfires in 3,000 miles and the other two had like 5K misfires in that mileage.
Now its time to drive it and see if its better.