[strtrydr]

I'm assuming you have checked to make sure all the bolts/nuts are torqued ...

If you have a rear sway bar, then I'd say check the bushings/end links. If you have a rear strut tower bar, check the adjustment jam nut(s) and the bolts/nuts that attach it to the strut towers.

Never had this problem when those struts where in my car so pretty sure you can rule them out as the cause.

Edit: Another thought ... have you checked your exhaust hangers/bushings for breaks/cracks?