On the passenger side, where all the accessory belts are. It can be heard faintly when the engine is idle, if you stick your head way down near the pullies/belts you can hear it better...it increases in speed as the engine revs but does not get any louder. Holding a screwdriver to the valve cover (nearest the firewall) you can hear it, but not loud, holding the screwdriver to some sort of bracket with wires hanging off the side of the motor, you can hear it alot louder. Holding the screwdriver to the mount for the tensioner pully, can't hear it, so it's something near the firewall. All the pullys/belts look fine to me, not wobbling or anything. I can't pinpoint what it is exactly. I have had a friend listen as well and he agrees it doesn't sound like any engine trouble (cams, etc.) but either a pully or the timing chain slapping against the cover.
