Installed new magnaflow exhaust today everything is fine with it no rattlles... but inside the cabin at 2500 to 3500 rpm or when the car is bogged down there is a bad vibrating buzzing that seems to be behind the seats way more when the top is up and windows are up. It must me something to do with the sound resanation in the car.... any ideas..... looking and looking help.

 

Get behind the seat and feel for anything that is loose. Then if you find something take a peice of cardboard and wedge in there for the time being. =/

 

It almost sounds metal. I have looked at the ribs & pivet points on the top. had someone ride with me and touch everything trying to find it .

 

You don't think it could be the tools in the spare? Mine used to do that.

 

I checked them... seem to be fine. Was it you jack???

 

There is a tray that you see if you look behind the seats. That used to rattle like crazy. It covers the spare tire.

 

Try getting a box that soda comes in and folding peices of that and stick it between your jack and what holds it.

In my car it was my jack. (I have an Eclipse)

 

How did you fix the tray?? card board??

 

I installed a new exhaust manifold a couple week back. Sounded great at first, but a few days later started to hear a metal grinding sound when accelerating and mainly when turning right. I looked underneath and the catalytic converter and transmission support weren't touching, but they were close. You could also see small marks that looked like they may have been rubbing. I readjusted brackets and hangers and the noise went away.

So while the pieces weren't touching while standing still, with acceleration and the Engine/Transmission/Exhaust moving a little they did touch. Something to look for.

 

I will get under the car tonight..... keeep the ideas coming.