about a month ago I bought a 00 z28 w/100k miles from an auction, immediately after driving it I noticed a loud banging sound coming from the rear passenger side of the car whenever I go over any sort of bump, kinda like something huge in the trunk is flying around(btw it's empty). I've tried taking out the jack and the spare, replacing the rear shocks, and having an exhaust shop make sure that no part of the exhaust is banging against the bottom.
My dad and I have basically run out of ideas, any help would be much appreciated.

 

hey, can you push the ear end of the car down when its parked up and replicate the noise or is it only when driving? Did you check the spring seating rubber and the spring itself to make sure its not cracked? Also does it do it all the time or only over big bumps, does sound strange it the exhaust is tight and the shocks are ok

 

we've tried to replicate it by pushing the car down and even by jumping up and down in the trunk but it only happens when driving, and it doesn't need to be a big bump even small ones will do the trick, as for the springs and the rubber seating i'll check those tomorrow and let u kno

 

ok have a look at those, but also while you under the car (you may have already checked) but look at the piece of metal that is under the gas tank above the exhaust muffler, this may be bouncing and hitting the tank? just a thought. Also basically get the car on standds and check the suspension panhard rod and contol arms and anything that is bolted on and give them a pul to see if it is loose.

If you cant replicate it pushing down it has to be something that is loose as its the up and down motion over the bump causing it. Let me know if you find anything and ill try think what else it may be.

 

we figured it out, one of the metal covers on the gas tank was a little loose and was hitting what I think is the stabilizer bar in the rear. but anyway the sound is gone now