When I go over a large bump there rear of the car sometimes makes a loud thunk or bang kinda noise. I removed all the tools so can't be that, and nothing else is in my trunk. My back end of the car feels sloppy recently so maybe something in the suspension? Any ideas? Anything make that noise that is a common thing to get loose or bad? I have a 2001 S2000. Let me know. Suspension is stock, 17" after market wheels.

 

perhaps spare wheel holder

 

Check your exhaust hangers, one maybe worn out or broken allowing your exhaust system to hit under side of car.

 

or your suspension could be shot.

 

could be suspension, but also check your rear sway bar end links. a friend had the same problem and it ended up being his right rear sway bar end link. Just a thought