I had a cat-back Flowmaster 40 exhaust put on my truck about a year ago and it just doesn't sound as good anymore. It just sounds stuffy. When I first got it I could crank up, pull out on the highway, and floor it and the truck roared. But now it just sounds muffled. Plus the truck is not near as responsive as it used to be. I've considered cutting the exhaust back and making a set of turndowns, but I don't even know if the exhaust is the problem. Guess it just boils down to not getting true duals. I kick myself everytime my neighbor passes by.

 

Do you still have a cat on your truck?

 

Sounds like a plugged cat. I seen something on here where you can check it with a temp gun aimed at the intake and output of the cat. I cant remember which should read hotter to indicate a good cat vs bad cat.

 

Yeah, there's a cat on my truck. But it was replaced by the original owner due to being plugged when the truck was brand new. Besides I thought a plugged cat rattled really bad.

 

No ... a disintegrating cat rattles ... a (badly) plugged cat makes the engine sound throaty. Just because it was replaced once doesn't mean it's still good.

 

A clogged cat will definitly cause u to lose power and throttle response you sould try removing the cat an test drive the truck to see if u gain any power back to eliminate what migh be wrong with it

 

You can take the cat on and off like that? I didn't know that. How do you get it off?

 

no, you have to cut it off

 

I had 2 factory cats on my truck go bad. The first was at about 1.5 years old, the 2nd one about 5 months later. Put duals on with 2 highflow cats and haven't looked back since. Don't know about now, but the in 99 the factory cats sucked!! Good luck. Jeff.