a few days back i noticed a odd noise coming from the rear of the vehicle (91 SSE) it sounds like there'* someone banging on a piece of sheet metal in the trunk whenever i went over larger bumps, not huge, but more than imperfections in the road. now tonight i was dropping off my girlfriend and i noticed the sound wasn't so loud but constant when the car was idling. so i went around back and listened underneath the car, it wasn't coming directly out of the pipes so it wasn't coming from the engine. it was like the vibration in the exhaust pipes were banging up against something. and it gets louder as you drive and give it more gas. what might be the problem here? it'* really annoying, but more than that i want to know what it is before it possibly gets serious. any help would be grately appreciated.

At one point mine was doing that because one of the exhaust tips was hanging on the pipe so a bump would make it jump up and down on the pipe could be that just a suggestion... try moving the pipe around with the car off with your hand a see if u can recreate the noise then find where its coming from. something is probably loose thats what I think :?

could be your cat. my cat (it'* the stock exhaust by the way) has a honeycomb cover on the bottom of it (part which faces street) and over time it has come appart from weather, road salt, and even the disgraceful extra long/tall speed bump.. that and 17 years of wear and tear!
Anyways i noticed that whenever I shifted into reverse (my engine makes a slight jolt when shifting to reverse), i'd hear a rattle which would go away after a second. At first i thought it was the transmission but then i noticed it was that same honeycomb cover that was braking appart and so parts of it would rattle and bump and rub the inner (actual) cat converter.

To try to remedy this , i was doing a fluid flush on the trans so i decided while iw as down there i might as well rip that old cover off... it fixed the reverse rattle but it caused a whole new 'scratchy/squeely' noise that comes off and on which may be worse, i'm thinking of putting some high temp insullation between the back of the cat (side facing car) and the underbody so that no metal to metal can come into contact.

Good luck and sorry for the long post
Mike Diaz

There'* a heatsheild over the muffler, it'* probable.

mine fell off and dragged on the ground. I remember when my mom first heard it, she though the transmission fell out of the car! that would have been messy! The noise you are hearing, I am thinking to be somewhere in the pipe is a little loose, and causing it to jump up because of that. If the muffler has excessive play [able to move freely up], then it is probably the rubber hangars which attach it to the frame.


-justin

most likely the exhaust,dont rule out anything in the trunk,maybe the spare?

thanks for the help, but i found the problem today when i could see. it was the cover over the muffler had corroded out around the screw so it was just sitting on the muffler. thanks again for all the suggestions

glad to hear that you fixed your problem!