The vehicle listed above has very low power. The truck has headers and exaust straight from the headers to a flowmaster muffler. I have had the heads redone, new cam and lifters, new sensors, fuel filter has less then 30000 miles on it. I performed a pressure test on the cylinders, the highest psi was 170, the lowest was 145. The truck ran perfect when i got it about 3 years ago. I drove it into a pond during the winter 2 years ago. it hasnt ran right since. everything listed above was replaced after the pond incedent. i also had gm goodwrench technicians install a new computer. The truck runs and sounds good but no power. Ive adjusted the timing and valves every which way to try and find some extra horses but it just isnt there. Im out of options. I would appreciate some expert advice, thanks.