problem with '95 Firebird

[wringer dinger]

My friend's '95 Firebird(3.4L with A/T) is making a rattling noise that sounds like its coming from the exhaust or something under the car. When he sits at a light it does it but then he puts it in neutral and it goes away. He says he hears it coming from other Camaros and Firebirds too so I thought somebody on here might know whats going on.

[Whit3Angel]

It might be his muffler. Mine does it when I'm in park or neutral and bring the rpms up. The packing inside the muffler might be old if its the stock one.

[GOLD_98_T/A]

check cat converter mine used to do that

[wringer dinger]

OK, thanks guys.

[busa4]

+2 either a cat or a muffler or hell could be both.