i have the same thing on my 03' just started recently though. on acceleration it sounds like a loose heat shield. what i did find the other day way the header heat shields are rotting away from the header bolts. i doubt this is the rattle i was hearing though. my rattle comes from under the front, or at least thats what it sounds like from the drivers seat.
i've asked my buddy to lay on the ground while i run him over so he could listen, but he said i was crazy??? what are friends for? trust between friends isn't what it used to be, huh.
