I'm new to the forum and new to cummins. My truck just feels weak. I was pulling about 7500lbs the other day and was not impressed. Almost couldn't pull 40 mph up a medium incline. My truck is 4x4 w 355 gears with an auto. Also working that hard I figured to be black smoking pretty bad but none. I do have a triple dog programmer set at 25% 3 1/2 straight exhaust.

 

Checked fuel pressure yesterday. 5 psi at idle drops to nearly 11/2 at wot. Lift pump time huh?