Rattle noise, Bad cat?

04gtdrop

New Member
Jun 10, 2005
532
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Sac, CA
ok, so i think i have a bad cat on the drivers side. I'm not sure why, cuse the car only has about 32k on her. and that h-pipe only has about 14k on it. i think maybe becuase she has bottemed out a few times, maybe that F***ed up my cat?

well i have a rattle coming from the h-pipe, you cannot hear it at the tipes, or in the motor. it sounds like its IN the cat. Like maybe a part of the inside broke off and is moving around inside the cat.

my setup is, mac pro-chamber h pipe with two hi flo cats duhh
and a mac cat back.

so i was thinking about calling mac in the morning to see if they would sell me just one side of the legs to the h-pipe. but i dont know if they will do that. any advice? i want to get this fixed ASAP, my car sounds like crap at an idle and while driving unless im over 3k rpms. :mad: :bang: :nonono:

any advice or tips? anyone else have this kind of a problem?

:shrug:

thanks :SNSign:
 
I have had my stang for about a year now and have had a rattle noise as well. Its a manual 2003 GT with about 35k miles. When I first noticed it, it sounded like it was coming from right under the drivers seat. I figured it was coming from one of the cats. I would usually hear this sound every so often while accelerating in second gear. The noise i hear is a really tinny/rattling noise. A few months ago, I changed the midpipe to a no-cats x-pipe and figured I wouldnt be hearing the tinny sound anymore. However I still hear it:bang:

Let me know if you find your problem.
 
I claim the same broken cat....at least that's what Ford tells me. Mine is stock mid-pipe. Makes a metal rattling noise in neutral and rev'in and while driving. I've been waiting nearly 4 1/2 months for warranty replaced stock part now...so I dunno if that's what really wrong or not.

Its possible, not sure how probable, that whatever may have broke up in your cat could end up in your muffler.
 
I had a similar rattle sound from my bbk catted h-pipe. I it was loudest at part throttle, sounded like something was loose in the bellhousing. It turned out to be a chunk broken loose in the cat. Try getting under the car while it isn't running and shaking the pipe to see if you can hear it. Maybe get a friend to bounce to car some while it is on ramps(not jacks or jackstands) to see if you can hear it. And if that doesn't work, try using a long screw driver to your ear or a mechanics stethescope to listen for it while it is running. If you can narrow it down to the cat, you might be able to take the midpipe off and shake the broken piece out one end if it isn't too large. I endend up just gutting mine with a really long paddle bit and a drill, but I have to short midipe for long tubes.