Maybe the pipes are my problem, I'm pretty sure its 2.5" at least. Is that what comes from the factory? If so thats what I have.

I dunno what else it could be, plugs, wires, cap, and rotor are all about a year old too. They are cheap plugs and wires though I'm pretty sure. Could that be some of the problem?

 

It may very well be the pipes. 2 1/4 inch pipes will only increase flow over stock by 12.3%. This is not enough to lose low end torque. However, 2 1/2 inch pipes increase flow by 38.9% over stock. This could very well hurt your low end power.

 

reading through old posts again...

after reading this i see that 2.25 pipes seem to be the way to go but does anyone know if the entire system has to be redone or would replacing the pipe between the cat and the muffler be enough? i have the stock y-pipe coming off my headers, meeting at a single 2.5" pipe, going 1 in 1 out on the stock cat, 2.5" back to the stock muffler location where i have a 2.5" y-pipe that goes all the way to the rear.

 

i have a 01 4x4 5.9 and i can barley spin my tires when im power breaking. So im loosing tons of power from somewheres to. Things i can tell yall is my muffler is cut off, still has OEM Cat. Im running rich. I do have 4:10 gears with 285 Nittos grapplers ( not even a week old, God dam screw driver ) ummm what else..oh i have no air filter in my intake ( is that bad? ) and lets see.....yea thats it. ANY IDEAS??????????

 

Not trying to be a jerk or anything here, but have you closely examined your exhaust system?

The way the stock exhaust system usually goes for the si/so converter is y-pipe to 3" pipe to converter to 3" pipe to reducer to 2.5" pipe to muffler to 2.5" pipe to expander to 3" exit. If you have a cat-back, everything before the muffler should be untouched.

If yours is 2.5" all the way through as you state, it'd be the first one I've ever heard of (that wasn't custom done that way).

I plan on replacing my "reducer" and 2.5" intermediate pipe with a 3" pipe here someday, and then having dual 2.25" pipes out the back. But for now, a high flow cat and Super 44 to single 3" is OK.

 

OEM cat can be your problem

GET AN AIR FILTER ON THAT DAMN TRUCK!!!

It really amazes me when people gripe about how these trucks are way under powered. By today's standard, they are, but when they were being built, they were mid range. Another thing people don't take into consideration, the engine design on these trucks were from the late 60's early 70's. Instead of complaining about how under powered we are, I say be amazed by what these trucks can do with what little they have in them.
That 3 speed tranny with overdrive really hurt these trucks in a lot of ways, but for an older truck, they still demand some respect.
(End Rant) (Been mulling those thoughts over for about a month now )