When I stomp the accelerator to the floor, truck shifts good till 4-5 shift. It will not shift into 5th till I let of the throttle. I got a Tech II today and no trans codes, but had P1093 Fuel Rail Pressure Low During Power Enrichment and P1621 Control Module Long Term Memory Performance, these codes were in the PCM but no code in Trans. I am running Edge on Level 4 stock trans.

Try changing your fuel filter... Im betting thats causing your issues

Fuel filter less than 2000 miles on it

I would still suggest changing it just to be sure... one bad batch of fuel is all it takes. If thats not it could be the CP3 or possible your fuel rail pressure relief acting up.

Connected Tech II, on hard acceleration the fuel pressure drops from 23100 to 2500. Commanded fuel pressure at idle to 160 kpa and held at 23100.

So now you just have to find out if its the CP3 or another issue as I stated above. Do a search on here, there is a way to test your CP3 without taking it into GM i seen the thread not to long ago.

Question, did it slowly start to get worse and worse or did you wake up one morning and it was a pig?

Also try removing the Edge before you do anything else and see if it resolves anything.

Best of Luck with it

When my truck had a bad CP3 it was a total dog. I had to p1093 code for a long time then a p1094 also showed up (low rail pressure at idle). My truck was a complete dog. With my PPE on level 5, my brothers stock dmax would out run me. When we replace it, it felt like a whole new truck.