I have a rattle around my stock headers, catalyst was stock and ok, i remove it to be sure, no heat shield was loose or craked except the upper headers heat shield that i remove but the rattle was still present under light acceleration when i release the gas at 4-5000rpm, i found nothing, solution?

 

Check the lower mounting (header to block bracket) likely cracked.

 

Bracket was ok, noise to, seem to be a heat shield rattle but nothing was cracked or loose...