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whitebird
11-11-2005, 02:26 PM
92 sc,131,000miles,strange matallic,rattleing noise,engine area,only afterwarm up and on the road and upon de-celeration only,thought it might be,heat shields,idlers,pumps or pullies all are good,will not make noise in driveway,reving engine...........what going on here!!........thanks for you replys...len

joenintiesc
11-12-2005, 12:58 PM
Well, if there are no other symptoms or mechanical problems, it may be nothing but a loose "something" that will only vibrate under a certain frequency (engine rpm, etc). I have all kinds of things in my SC at 190,000 miles that vibrate and make noise in the dashboard, inside the door, somewhere under the rear interior trim panel, etc. Almost impossible to track down! But I would double check the heat shield on the cat anyway - it may not feel loose, but could still be loose enough to vibrate and make a racket.

90coug
11-12-2005, 01:27 PM
Hmm... I had a similar problem; it ended up being the Super Charger Bypass Canister. A screw for the rubber tube right by it wasn't positioned right and when the bypass canister opened it hit the screw and broke and now it rattles, rattles like you are describing. Good Luck

peacefulruler
11-13-2005, 10:54 AM
I once had a rattling noise at idle or decel...the Catalytic Converter matrix had worn out so much that there were loose chunks of metal inside them. I actually had a chunk break loose and get stuck in the outlet, at which point the car lost power. I had to have it towed (NEVER drive a car with the exhaust clogged!), changed that CAT, and everything was fine.
My other CAT is starting to go...I'd bet that this is your problem.
Idle the car, block the wheels, then get on the ground, first by your driver's door, then the other side. If it's the CAt, you'll hear the sound coming from them, right under the car.

Best of luck,
Fred