Sorry to tell you, but its the dreaded autotensioner. Every 5th gen has this problem. Welcome to the club.

100% guaranteed. How do I know? I just dropped a boatload of cash to have MINE fixed. It make the exact same noise. at around 1600rpm to 1000 rpm. Above that it is fine and at idle it is fine.

The autotensioner isnt doing its job (IT BE BROKE!) and what you hear is the timing belt rubbing up against the timing belt cover.

Its about $600 with parts and labor through the dealer.

Good Luck.


(Im not sure where you get the "3-4000k" rpm range.)