i got a 2001 dodge ram 1500 with the 5.9l I have done EVERYTHING to this truck. new tranny a year ago. Just did the intake and plenum gasket, plugs, dis. cap and rotor. Didnt fix my problem. The motor runs like a dream! but, no power on the highway. Ill put the pedal nearly to the floor and it takes about 60 seconds to get from 60 to 70 without downshifting. I have 285/75/r16 with a flowmaster muffler. Only aftermarket things done to the truck. Brought it to my local exhaust shop to have the cat tested and they said it wasent plugged. I am stumped. They seem to think something is wrong with my tranny but that makes no since. It shifts just fine and have no codes at all. My mpg is horrible too. 12hwy and 9 city. When i first got the truck i used to get 15-18 on the highway. Whats going on? Not sure what my next plan of attack is