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Discussion Starter #1
I have a 2003 Mustang V6, Had plans to get long tube headers + o/r xpipe, and new mufflers, havent decided. I currently just Have 2 flowmaster. Just yesterday I shut my door and heard a rattle...I got under my car and had a friend shut my door, and found out it was my right catalytic converter, sounds like its got a leak or something...Im guessing its just old pipes. BUT Here's the situation: should I just cut my cats off and reweld just pipe til after christmas? Or should I buy another cat? Between my check engine light just come on my guess is that its referring to that too.
Thanks in advance
 

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take it to autozone or any other place that'll read it and figure out for sure what is going on, if it is just a bad cat and you plan on getting rid of them later then sure go ahead and straight pipe it so you can get the feel for what the car acts like without almost any backpressure....

you would only hear a "leak" if the car is running not a rattle, most of the time if the catalytic converter is still good and it rattles it's just the heat shield on the outside of it that has come loose, mine came off after "speeding" down the highway lol

be sure to let us know what the code is!!
 

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Discussion Starter #3
Thanks for the fast response, are you telling me taking the cats off are bad? Im all for learning something new lol. I had plans to get the o/r xpipe, but if thats not ideal to go catless ill reconsider,

I feel slight grinding or vibration now when my car is idling. I plugged the obd computer in and it said right side running lean...same side of the unknown cat problem. Any ideas?
 

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was the code for the front or rear O2 though? from what you said it shows bank 1 lean but does it say "bank 1 bank1" or "bank 1 bank 2" better yet, whats the exact code?

if the code is actually for catalyst inefficiency then yes it is probably the catalyst inside the cat that has come loose and is vibrating, that can happen when they go bad

without the cats it'll be a tad slugish on the low end but will regain that on the top end, you get a trade off in the powerband of sorts.....
 

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was the code for the front or rear O2 though? from what you said it shows bank 1 lean but does it say "bank 1 bank1" or "bank 1 bank 2" better yet, whats the exact code?

if the code is actually for catalyst inefficiency then yes it is probably the catalyst inside the cat that has come loose and is vibrating, that can happen when they go bad

without the cats it'll be a tad slugish on the low end but will regain that on the top end, you get a trade off in the powerband of sorts.....
System Lean Bank 1 thats all i know. So no cats lose acceleration..i never knew that, i honestly didnt know it made a difference...might consider a catted x pipe now.
 

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get the full code, there could be other causes to the bank 1 lean code....

the do hurt the low end some yes but you gain it back, you trade for low end tq to get high end hp, a good balance would be a set of high flows.... got some of them on mine, they also help keep the sound quality under control if you keep some form of cats.....
 

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If it says bank one cutting the cat out will leave a check engine light but if it's bank 2 it won't bc it's before the last cat and from what I'm told no cats makes it sound like a tuner
 

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Thanks for the info guys, I took it to my local muffler shop and we found out together I had broken my passenger exhaust manifold lol He said he could get another one and installed for $200. But He re-welded it for about 20 minutes so im guessing its good for now. Charged $20 he said if it happens again might as well replace it. So apparently it wasnt my cat rattling it was my pipes :disgust:

---------- Post added at 10:00 PM ---------- Previous post was at 09:59 PM ----------

And between the check engine light went off...so we're good :headbang:
 

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Yeah that's a common problem since the ac line drips on the header, everytime you turn it on the condensation from it drips on it so they tend to get weak and crack over time, that weld will hold longer than the metal around so it probably won't break for a while..... Glad it wasn't anything too bad....
 
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