Acceleration, or not so much...

[BobLabla]

I am having an issue with my 2009 cm871. New to the boards well... I've dumped too much money chasing this issue and need help. So when the truck has been operating for a few hours, it starts to run hot as hell and without the heat on, windows open it's about 100 in here easily. It doesn't say it's performing a Regen but still kicking the fan on and creating a sauna in here! With that is a horrible hesitation / power loss , so bad sometimes I won't get a response till about 3 seconds after smashing on it. Then it will shimmy a bit and then get on its way.... Very slowly! Idles okay, never any codes, but what I have noticed is that it doesn't rev to the normal range, kinda flatlines at about 15-16 hundred. Fuel milage in the dash reflects 6.3 or so, but all I ever haul is cardboard