To optimize torque, you need to set your system up right -

 

shoes or pads on the back? i had that same problem when i first purchased my truck never knew just thought it was the 4.6 being weak. My shoe's had heat cracks in them. Thats how i figured out my wheel cylinders were bad.

 

I'm getting the exhaust redone in the near future (back to a stock configuration most likely), but the pipes have been on there for several years now with no negative effects. This power issue (or lack thereof) is new - nothing on the exhaust has been changed in the last 40-50k.

 

The pads are new all around - I just had the brakes done recently.

 

If it's changed that much, that's noticeable recently, then I would do a compression test. You still within parameters with no check engine light.

Regardless of what you may think, exhaust in always an issue. The best setup for these trucks from stock has always been High flows w/a 3" cat back and either a Magnaflow or Borla XR series muffler. That set up has shown an increase in low end torque without moving the powerband up further into your RPM's. Just keep that in mind. The goal should be to put torque and power were you use it most. Not so much "more" although it's a bi-product, -it's where you need it. - Usable. That's what I set up for and I pull 1.5 times my weight, without a problem. I've installed headers and pulled the flange ends on a set of high flows, welded my own in. 3" ID to slip fit collectors and 2.5 OD's to connect the Y. Then went with a 2.5 Cat back into a 9" Magnaflow muffler. Big difference! I keep up with traffic under normal acceleration pulling heavy.

 

Thanks Jbrew...that sounds like the route I need to take with my exhaust as soon as I get this power issue sorted out.

 

Its your rear brakes dude.

 

If you have rear discs, I'd bet the E-brake shoes are dragging..........

 

Sounds good.

BTW- I recall installing new pads and rotors on my old 99 diesel. They smoked and got hot. I thought maybe it was a break in thing, so I let go for about a week. noticed they still smoked after a week, so I removed the pads and took them back into Carquest. Sure enough, they sold me the wrong pads. The right ones were shaped a little different.

It was just a pad thing in my case.

 

have you tried kicking it in neutral and checking to see if your brakes were dragging yet? i had a brake start dragging on my '97 (just one, the front left caliper went bad) and my truck had NO POWER. couldn't hardly get over 55 without flooring it...but i'm a mechanic...so i instantly knew it was a brake dragging. when i got out of the truck i started sniffing at each wheel...at the front left i smelled nothing but barbequed brakes...replaced the caliper and all was good again...

 

I'm in the process of checking the brakes now. I'm noticing that the problem seems to be less noticeable until after I have driven a couple of miles - when I drive the truck for the first time of the day, the problem doesn't really show up until I'm a mile or two down the road.

When I'm turning the wheels over (with it jacked up) should I be able to hear pads rubbing the discs? On the fronts I could hear faint rubbing of shoes the on the discs when I jacked it up.

I do have rear discs - how would I check the E-brake shoes?

 

when you find one really dragging, you'll know it. the faint rubbing isn't a big deal. when they are really dragging you'll have trouble turning the wheel. that's when you know. on the backs, same thing...you'll know when you find your problem.

 

When jacked up, wheel should spin freely, to a point. The brakes WILL stop it. They have to touch the disc. But yea, the wheel should spin 1 revolution or so.

 

Ok the truck is up on the jackstands outside - the rears are significantly harder to spin than the fronts, which I kind of expected since the they are having to turn the drivetrain. I get between 1/2 and 1 revolution on the rear wheels when I spin them. The fronts got closer to 2 or 2.5 revolutions.

 

After looking at the E-brake cable/spring assemblies on the back side of the rear hub/rotor, the drivers side spring seems significantly compressed when compared to the passenger side one. The tooth/catch that the spring is hooked to and in turn controls the e-brake is actually about 3/4 of an inch forward from the back of the slot on the drivers side while the passenger side is all the way at the back of the slot.

I'm guessing these weren't replaced when they did the brake job since I didn't specify it - I had always assumed the E-brake just functioned thru the primary brake pads/caliper.


Jbrew - I just checked the pipe diameters on the exhaust as well - from the factory Y-pipe back to the Flowmaster SI/DO muffler is 2.5", and from the muffler out to the exhaust tips is 2.25". Everything is factory from the Y-pipe to the manifolds.