rattling noise??

[LS1PoweredZ]

Sometimes when I'm drivin and lay off the accelerator I hear this weird rattling noise that sounds like its comin from the rear of the car. I let my cousin use my Z for a date last week & he said he brake torqued (I tore him a new a**hole cuz he was only supposed to drive the car, not show off), but he supposedly didnt hear anything while drivin it back to my house. Could the brake torque have done anything? Any ideas or suggestions? Thanks guys.

[Migforce]

I got a similar problem, it happens when the car is cold and goes away when it is warmed up. The only explanation I have is that the noise is caused by backdraft through the exhaust pipes.

Basically...When the exhaust pipes are cold. You press the gas pedal air pressure in pipes goes up (as they fill with warm exhaust). When you let the gas pedal go, besides the gradual drop in pressure (as there is less gas rushing down the pipes) you also get a bonus effect of your pipes rapidly cooling the gasses already in the pipes resulting in temporary vacuum forming in the pipes. So outside air rushes into the pipe colides with air going down the pipe causing gasses to vibrate and make that annoying clapping or rattling noise...

Short version...same principal as someone blowing into a beer bottle and making it whistle.

[kenhanson]

i had a rattle that was driving me crazy.....it turned out to be the spare tire squeaking, i just tightened the center wing nut and my sanity was back!!

[camaro8392]

holy crap same thing is happening with the rear of my car too......i took out the spare tire and jack and the noise is still there.....its really annoying its like a knocking and rattling sound.....What could be loose thats making this noisE?