I have a 2002 XLT super cab with a 4.2 w auto . My question is the truck sounds like it has a exhaust leak but I have checked all the manifolds for cracks and the bolts for tightness. After the connection from where the manifold connects to the exhaust pipe there are two little muffler like pieces installed in line . I know that the second is the cat converter. but what is the first one. It sounds like the noise is coming from one of the two little can like pieces but it sounds the same on both sides . I own a 81 f150 w a 300 six and know all the usual sounds the make. Could it be just the nature of the newer fords.

 

First off, those two small things are cats also. Some people call them cats, some call them pre-cats, resonators, and um, there's this other name i can't remember, has the word "warmer" or something in them.

Anyhow, our trucks are known for vibrating, rattling, clanking, chattering, whatever, from the cats. This typically happens after installing an exhaust or muffler. It's the heat sheild vibrating. Mine does it, and it gets worse everyday. Cool, huh?

As far as an exhaust leak sound, i'm not really sure what that could be other than the obvious.

I've also heard about a metal piece inside the cat that loose and eventually blows itself out. Not sure about the validity of this rumor though....

 

If it's rattling, it may not be the heat shield. I removed my heat shields, and it still rattled. I then removed the section of pipe with that converter in it, and when I turned it upside down, broken pieces of converter brick fell out. Turns out, they are also known for the converter's breaking up and rattling. If that's the case, just get some aftermarket high flow converter's and have your local muffler shop weld 'em up. Go to Motorhaven's site , they have some on their site.You can replace two stock cats with one high flow unit and still be legal.

 

The truck does have a flow master muffler installed . The sound isnt a rattle, I noticed that the exhaust manifolds are like paper thin. Ive owned trucks with headers on them and they have that exhaust pulse sounds that almost sound like a leak but its just the thiness of the manifolds. Its just one of those sounds that catches your ear if you have the window down from time to time. And I was curious if that was just the nature of the truck. Other than that the engine and truck are as smooth and quiet as a mouse.

 

That and the roaring of the clucth fan.