all right peoples maybe someone out there can help me pin this down.

so after an hour drive from chicago i come home to hear this squeak.
this squeak only happens at IDLE. from far away you can't hear it but sittin in the driver seat top down its F'in annoying. it sounds like a belt type of squeak. MY05 is got 15k on the clock. i've lubed every pulley and even applied some belt dressing to the drive belt. i even thought maybe the tensioner was giving up but no its tight. the belt is tight no excess play in it. i thought maybe it would come from the head but nothing inside the head could squeak like that. i could be wrong though. Please if anyone out there has experienced this or even know what it could be PLEASE chime in.