i have a annoying rattling noise next to my cats..or around that area. i know that the cats arent bad and i know its noy my alternator. i tighted all the nuts that were visible.

any ideas aobut what it could be?

 

man its annoying

 

try the head shields.

 

i also noticed a rattle on mine. maybe it's just to balance out the rattle on the inside too. i may take it in to the dealer if it gets worse or a nice sunny day for an 07 loaner.

 

i ahve high flow cats. with no heat shields

 

friend of mine with AAM HFC was having this problem, initially thought it was a heatshield. had the heat shield tack welded in a few spots and seemed to do the trick a little bit...two days later he was spitting out his cat-brick...you may be having a similar problem, take the cats off and see if anything is loose inside.