IMRC ??? Rattle noise

[vnmuss1]

Fellow Snake Charmers,
I have a 96 cobra with a KB Blower. Just started noticing a rattle noise(sounds like a loose bolt somewhere) which seems to go away as I reach 3400rpm. It is not very load but is driving me nuts.
Has anyone heard of this, maybe in relation to the IMRC's.It is very fant when the car is not under load. When I drive it cold it is the loudest.

Thanks,

 

[cold96snake]

Detonation. get it tuned.

 

[Silver66FsBk]

maybe you have a busted Cat?

 

[vnmuss1]

Cold and Silver,
Thanks for the reply, Looking into both.