Loud "CLUNK" from rear over sharp bumps

[socratic]

Jim, thanks for letting me know what those big bolts near the center brake light are.

Maybe it's wishful thinking but I swear the clunking is less frequent and less severe with the mild finger tightening that I did of the "cap" on the big nut.

Next time I get a chance to get on the hoist I'll see if it's the sway bar bushings or a lower control arm (I'll have to check the manual to see what that is first so that I can look at it).

Fortunately it doesn't seem to be the engine mounts because I did lots of full throttle acceleration runs and no funny noise or effects during the runs.

Also I'm thinking it isn't a strut because the clunk isn't a bottoming out sound, which is quite harsh and the whole car would shake (I think). Also the car handles and rides well and so this should also mean that it isn't a strut.

Maybe I'm throwing you helpful people off due to a bad description of what the sound is like. While it is a "clunk" sound, it sounds if something is loose when I go over some kinds of bumps. But not all kinds of bumps. Driving slowly over speed bumps don't produce the sound. And many sharp bumps (e.g potholes) don't produce the sound. But some kinds of sharp bumps do make something shake in the back. I wonder if it could be a loose muffler or exhaust piece.

Thanks again for the advice so far.

[AndyF]

I was getting a similar clunk from the passenger side of my 98 Boxster this spring and was worried about it being from the rear passenger side suspension. I first noticed it after taking my hard top off after winter driving. I realized after the a while that the front passenger side of the Tonneau cover had some play in it (where the driver side did not) and that the noise was largely absent with the top down (and possibly cushioning the tonneau cover on that side).

Dealership just adjusted the tonneau cover at my service this week and the clunk is gone.