Just got another truck. Cranks fine, hot and cold. Drove home when bought it and had to slow down pretty good on interstate, when speeding back up it was like I was taking foot on and off accelerator. Once it gained speed back it was fine. Then, got off at exit and going up hill it did it again and worse. Loss of power and not downshifting. Codes are 0236, 1698, 0382. But none seem to correlate with what it is doing. Itn has high miles and a new trans. Anyone have an idea? Thought about vp44 but just don't think that is it. No fuel pressure gauge yet either.

2000 3500 QC, 4x4, Auto

 

Check your batteries. Disconnect them and load test them individually. I had a bad battery on the passenger side that was causing various issues, the worst being dead pedal. Voltage was good on a regular test, but under a load, it would drop to 2-3V. When the batteries were tied together, the gauge in the truck was normal. Replaced both batteries and all of my issues went away. Hopefully, it's an easy fix for you.

 

Have you checked and cleaned your grounds? 2nd to the batteries (always change both batteries when one is bad) I would clean up or even run new ground wires.