In D truck won’t go above 2k, in P revs to 3500

[06DDLBZ]

Put a donor motor in the truck drove it for the first time and it would not get about 2k rpm. It’s shifts and still goes up and down the mph range drove it 80mph but feels like a limp mode. No CEL. When truck is in park I can stomp the pedal and redline it.

Truck has a Calvin’s stage 5 with a goerend R converter that was restacked by the only Allison dealer here. Truck also has a GT3794VA on it that’s brand new.

I’m not sure where to start. I have a tech2. No codes in trans on ecm.

Fuel rail pressure is the same as requested.

Kory Willis tunes, had his TCM tunes but it TCM fried and just reprogrammed new TCM with GM Tech2 software. I wouldn’t think this would be the issue since it’s all new software on an all new TCM.

Anyone have any ideas? I don’t know if it’s a software or hardware issue.

 

[06DDLBZ]

Turned out to be a bad MAF with a no CEL. Identified by tech2 reading.

 

[HWI]

Same thing happened to me and it was also the MAF. I also had no CEL codes when I checked it with the tune installed, when I switched back to the stock tune it popped codes. I think the tunes change the MAF tables enough that it won't trigger a CEL, just a guess. But for anyone in the future reading this thread might be worth reverting to stock tune to see if you get a code.