i've started hearing a new noise in my car... it sounds like it's coming from the rear-passenger side... It seems to happen when i brake/accel, and sounds *EXACTLY* like the sound a ping-pong ball makes when it hits the table... it seems to only happen under heavy braking, but on normal acceleration. I just took a quick glance back there, and everything *seems* ok... but this sound is really annoying ... any ideas?!

 

Something's loose!

 

My friend with a 94 LS sedan is experiencing the very same thing (i think).. it used to always happen whenever he disengaged the clutch.. it'd make that popping noise like a ping pong ball.. and later on that day the car would make the sound whenever the car was in motion.. so he took it to a shop.. the mechanic thinks it might be a loose bolt in the shift linkage

 

check the tires for irregularity (such as doing a burnout and draging the back tires to the point that it gives them a flat spong....hehe like that VW loaner my boy killed)

thats all i can think of