I have a nasty crackling sound coming from my car when its idling. Its most noticable after the engine is hot but I still get it when I start the car cold.
I used to think that it was the heat shield on the CAT because it is louder on the passanger side but I cut the CAT off and I'm still getting the sound.
All the heat shields under the car seem tight and don't move around, nor does the exhaust from what I can tell.
Any ideas of what to check next would help alot because it is driving me crazy and doesn't sound to good when I pull up next to a rustang

 

does it vary with engine speed? if so, then i'd be willing to bet its a hole in the exhaust somewhere, if it doesnt vary, or if it goes awway when you rev it up, its metal clanging together somewhere... when i had my 83 z28 i plugged the holes where the old air recirculator tubes? were, and when a pipe plug fell out, it sounded like *ss. even worse i was at school when it happened oh well, crap happens