so i had this rattle problem since i got the car...(02 6spd...52k now) ... when u start the car cold or warm..u hear it rattle very quick and goes away at idle...everything is fine when ur driving just as soon as u let go of the throttle to decrease speed it rattle like a ****...horrible sound...i jacked up the car and had a friend rev it foir me and it only occures when rpms are decreasing...its deff not the ypipe...but sounds as if the cat cage is loose and is rattling...i even had the hood open and checked for the sound and its coming from the back of the engine...all heatshields are off of the car so its not those...i cant figure it out for anything...any ideas?..hopefully headers and y(aftermarket) fixes the problem...

 

same symptoms I'm having dude. Mine only does it once the car is warmed up and from about 2,000 RPM and below. Noticed it for awhile and I thought it was a heat shield too.

Do you have a SES light on?
I don't come on the forum frequently but have been seeing some people talk about the baffles in the cat' coming loose and It sounds like that may be the problem.
Some say they break loose, and if the pieces are small enough I'm sure there is a possibility of them ending up inside the engine....


I too have an '02 6speed... but with 150,000 miles

 

^^ nope no ses light..just a big ol rattle...i hate it...so i guess i was right about the cat cage being loose?...

 

i have the same problem with mine but the rattle i hear is the cat...it broke inside the plates and now it rattles when u get off the gas....ill be replacing that very soon...

 

If you really want to find it try this. Jack the car up and hit the exhaust with a rubber mallet. That should let you hear any rattle from the exhaust. You just can't use a metal hammer because it will "ring" the exhaust like a bell and you won't hear the rattle.

 

^^ ohhh good idea

 

Precats or main cat ceramic broken?

 

could be a precat hanger, OR it could be one of the hangers on the mid piping.......I had both problems and based on your description this is what I think It might be

 

precat or noisy timing chain.

 

nope not the timing chain ...it has to be the precat

 

Mine was the exhaust hitting the cross member under the car and behind the engine. I think my motor mounts are bad. Its a bad drone when you get on it. I all started thanks to walmart.

 

its definitely not the exhaust hitting something. Certainly sounds like an internal cat rattle.... ill have to get under there and hit it w/ the dead blow as recommended.

 

Mine did the same thing. It was the cat. Either gut it or get a new one.

 

Bank 2 (rear) cat???

I'm worried about getting it off the car; how much trouble, rusty bolts? PA car.....

 

Its most likely the rear precat

 

I got that figured out. I just know the rear cat is in a difficult place and working with exhaust bolts usually involves some trouble and/or breaking bolts, on top of getting to this pre-cat.

 

I got that figured out. I just know the rear cat is in a difficult place and working with exhaust bolts usually involves some trouble and/or breaking bolts, on top of getting to this pre-cat.

 

It all depends on how much rust there is. My Florida car came apart easily when I did my header install. I could have reused the nuts and bolts.

Give it a good soak with PB blaster. Start soaking it the night before if you can. Other than that you just have to get in there and do it. Just be prepared to handle it if a bolt brakes.

 

you will probably have to break the studs or they might come out. Heat them up when you are trying to get them off. Then just use new bolts

 

I have the same problem. I changed my oil this past weekend and noticed that the "wire mesh" like material surrounding the front exhaust had rusted thru on the front side and there was a 1/4 gap where it used to be attached. The mesh reminds me of the "flex pipe" that was on my Saab 9000, only this is surrounding a solid piece of metal from what I could see. I had my son start the car, (bad idea) and rev the engine. Thats where the noise is coming from, I'm going to go to a muffler shop and see if they can weld that mesh back in place or remove it altogether.