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Hello all....

I have catalytic convertors that are dying in my 2005 Mustang GT. I've taken my mustang to a handful of different garages and they all say the same thing. I've replaced all four o2 sensors but I'm still getting a cat warning/check engine code.

I thought I'd try to take them off... so I cut them out and unscrewed the "Heads" (for lack of a better term. The bracket towards the engine). I took a good look at them and blew some compressed air into them... they looked ok to me... I did..... run some water through them... not sure if that's a good idea or not... I wanted to see if they were clogged and the water ran straight through.... So I let them dry out and thought... I'll put them back on.

I bought a 2.5" exhaust pipe/sleeve to join them back up and bolted the joint together, super tight and I screwed the "heads" (for lack of a better word) back in, super tight and my cars is WAY too loud. It's almost like not having cats on at all.... or like not having a muffler... It's super loud. But I can't figure out why... where is the noise even coming from? It seems to be coming from under the engine... but it's hard to tell. The car runs ok...

1- Any thoughts on this?
2- Anyone know where I can get some good new/used Cats? Is that even legal? I'm in California.
3- I don't want to have to pay the 3k$ for new cats at Autozone....

Thanks!
 

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1) my best guess is you have a leak -- maybe get the car up on ramps, start the engine, and get under there to see/hear where the noise is coming from

2) I think that it is going to be very difficult to find new or used cats cheap . . . I think there was someone on here that mentioned selling a set a few weeks ago, he was advised to keep them to avoid the situation that you are in, I'm guessing they are long gone by now. I would check with as many "salvage yards" as I can find on line. I think that if you have the original-looking cats installed, and they pass the emissions test, you should be OK in California. Technically any modification to the cats is illegal, but they must allow for repairs.

3) I would not want do to that either

4) search the forums for threads on "anti-fowlers" or getting car to pass emissions with aftermarket cats or no cats . . . I think there are some tricks where you can extend the O2 sensors out of the main flow so they will report that the cats are working, to pass emissions inspection
 

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Check americanmuscle.com. They have catted x-pipes for as low as $399. Give them a call to see if they meet California emission requirements.
 
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