I was pulling a 6500 piund trailer last weekend and i noticed that i was getting alot more black smoke that usual and i got down to 35mph pulling a hill at one time and that was on the interstate. This motor only has 68k miles and has all new injectors and return lines, and a new fuel filter and base. I hate to pull the pump and it end up being a little something i overlooked. What do you think my problem might be? thanks

Sounds like your problem is a stock 6.2L
Last time I pulled a 3t trailer from FL to VA beach mostly on I-95 I didn't run into any big hills but the hills I did go up slowed me down to 55 mph.
That was before I knew about the hill trick.
When I came back from Maine I had trouble maintaining speed going up hills because my truck had a ton of crap in it, one thing that I found helped a lot was to find a larger truck going about 55-60 and drafting it up the hill.
Cheating your trucks Cd (cofficient of drag) helps alot.

that makes sense, i think i'm going to spring for a turbo set up.
i love the fuel mileage compared to my old truck with a 454 but when you hit a hill in that truck it just would not slow down.