I know this is a difficult way to find an answer but when I'm driving I hear a rattle under my car. It doesn't sound like its metal, its more like when you fling a door stopper but very gently and if it was made out of plastic. When I hit a bump it rattles louder. I checked my tie rods but they are fine. Is there a good way to diagnose this problem?

 

Maybe sway bar end links. They sound more like baseballs in a bucket to me.

 

Had a sound coming from under my car about a year ago. Sounded like a baseball rolling around in a plastic bucket, mine was a bad shock. Replaced it and the sound was gone and had less of a shimmy at higher speeds.