I've got a new noise and am wondering if anyone knows what it might be. The noise is a vibration noise, kind of tinny(tin) and changes with RPM. It sounds like it is coming from inside the dash behind the instrument cluster. It happens during deceleration when RPM is higher than 3000. It is not the clutch, I've had that before and it definely sounds like it is inside the cockpit behind the dash.

Thanks for checking my post and extra thanks if anyone has clue to what this might be...

 

check out passanger side visor...
believe or not... my noise what seemed coming out
from the dash was actually caused by passanger side visor...
try leaving it half way opened and drive around...

 

I've had some strange vibrations and / or rattles also! You may want to check the heat shield between the exhaust and the battery. Look for clearance between the post that the heater cable end attaches to and the shield. May car had about 1/16 clearance, but the paint was worn off. I increased the gap to 1/4 inch, the noise disappeared. The shield can be moved easily, just push!

 

I've been trying to locate the source of a thunking sound when I drive over sharp bumps in the road. I was convinced it was something under the dash until I read a post about noise coming from sun visors. Sure enough, when I put my sun visor down, the noise stopped. Turns out that the visor has a way of being jarred free of contact with the windshield frame when driving over certain bumps, and the visor makes a loud noise when it snaps back into place.
There's a quick fix that worked for me... just glue a soft spacer to the plastic tab on the top side of your visor so that the vibration is absorbed or dampened. No more noise!

Gary