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-   -   rattling at idle?? (http://www.wranglerforum.com/f210/rattling-at-idle-48351.html)

wrpracing13 04-07-2010 05:35 PM

rattling at idle??
 
i got a 03 tj 4.0L, i was sitting in my driveway before idling and i heard a rattling coming from underneath. it sounded like it was coming from the cat? i have pretty much no clue what that means except for maybe my cat is shot and the insides are just rattling around. Also my check engine light comes on every once in a while, would a bad cat have something to do with that? let me know guys, im not a master mechanic and any help would be awsome. thanks :punk:

Jerry Bransford 04-07-2010 05:38 PM

Take a rubber mallet and tap firmly on the cat to see if you can duplicate the rattling. When a cat goes bad, its internal ceramic element can break up into small pieces that will rattle loudly at idle. Mine did the same thing. :)

distortedtj 04-07-2010 05:59 PM

Quote:

Originally Posted by wrpracing13 (Post 592605)
Also my check engine light comes on every once in a while, would a bad cat have something to do with that? le

YES.

and what jerry said.

Schmo 04-07-2010 06:06 PM

Have you pulled the code to see if the CEL goes along with a CAT issue? Hopeully you'll still be covered under the 7 year 70K mile emissions warranty, otherwise, it ain't cheap.

jvinch76 04-07-2010 06:32 PM

i had the exact thing you described,

one of the flanges on one of my cats was loose and rattling, made the car sound like trash...i tightened down the flange i think it was a 14mm or a 15mm and the rattling went away

InfernoGirl 04-07-2010 06:52 PM

Yes to all these things. If it were me, first (when it's cold) I'd lay down under it and shake the exhaust to see if you hear a similar sound and see what's loose. If you don't notice anything loose, I'd do what Jerry said with the mallet. Since it's throwing codes it is likely a cat, but it's quick and easy to look for loose parts first...

wrpracing13 04-07-2010 09:43 PM

ok thanks. i havent gotten a chance to run the code yet, i gotta borrow a scanner from my friend. i bought the jeep used so i dont know if it still has the warranty, its only got 57k on it. if the cat is bad, how much am i looking at to fix it, i saw a new cat isnt that much but im guessing labor is gonna kill me.

distortedtj 04-07-2010 10:19 PM

Quote:

Originally Posted by wrpracing13 (Post 592841)
ok thanks. i havent gotten a chance to run the code yet, i gotta borrow a scanner from my friend. i bought the jeep used so i dont know if it still has the warranty, its only got 57k on it. if the cat is bad, how much am i looking at to fix it, i saw a new cat isnt that much but im guessing labor is gonna kill me.

No need...Simply turn the ignition switch On-Off-On three times within five seconds then leave it in the On position. Don't turn it to Start, just to the On position. Then have patience, it takes a while for the diagnostics to finish & any codes present to show up in the odometer display.


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