I just got my first ever mustang a couple weeks ago from a little used car place. I expected some used car salesman crap but to be honest I had always bought from private sellers. It has a little below average miles per year on it for its age but there is normal wear and a couple little things I will have to do on it but expected it to be sound as far as safety inspection. I had noticed a slight "clunk noise" in the rear when driving, only over rough spots in the road. Almost like a spring or shock moving where its seated. It doesnt do it on smooth and it doesnt feel rough overall but its noticable. I had mentioned it and they said it was normal with these cars. I read some thing about road noise being a common complaint with these and I had been driving a 94 f150 prior to this for a while so thought maybe I'm not used to it. I had taken it to a ford dealer to have the airbag recall done and they do a mandatory multipoint inspection and said everything visually looks great on the car, but if I have any specific concerns they would have to obviously charge a diagnotic. Not sure what to think. Anything I can check myself?

 

Check the shock mounts, from inside the trunk, tighten them up a little, see if
it goes away. They're easy to replace if the bushings are bashed... They
won't move unless the bushings are bad, top or bottom.

If you have a rear sway bar, could be the links or bushings.

Then the UCA and two LCAs.

They do make noise, I had to sound deaden the trunk in mine, it would bong through
the spare tire well. All good now...

 

Blackcat89, 08'MustangDude makes very valid suggestions. I would also lube/replace all rear suspension grommets. I would pay particular attention to your rear sway bar mounting bracket grommets. When hearing strange noises when going over bumps it's usually a sign the rear sway bar grommets need lube. Don't worry, this is a fairly common problem.