I am leaning towards the exhaust leak. The truck has been sitting about a year, was hit on d/s rear bed. When I bought it the truck was on empty, I am wondering if the fuel pump may be bad? I put it on the rack at work, I work at a 4wheel drive shop, this morning and the fuel filter is brand new, new 02 sensor, the plug wires are in the right firing order. The exhaust leak is horrid! Looks like quite the pita to get to the bottom manifold bolts. I did tighten the uppers, they were pretty loose. Looks like the po had the exhaust completely redone, from manifold back, new cat, muffler, down pipe, and tail pipe. I picked this truck up for $340 and it is mint, minus the bed. Factory bucket seats, floor $#!& auto, full gauge package, a/c that works, cruise that works, pwr windows and locks. Could the TPS be the issue? The thing runs great in all aspects except initial takeoff.