1999 Ford Mustang • 6 cylinder •

I have a 1999 ford mustang v6 I hear a sound that sounds as if a heat shield was loose on the car but its not my heat shield when I put the car in drive not moving I hear it but when I start driving the sound goes away but comes back when I slow down to stop and sometimes when I put the car in park I was told a flywheel could do that is that true?
January 14, 2011.

I never heard a flywheel make that type of sound. Take a rubber mallot and tap on the exhaust. Chances are the insides of the catalytic converter, muffler, or resinator are loose and that is what you are hearing.