2000 Expedition 5.4L

This occurs intermittently, but when it does it sounds like a raspy buzzer and it originates from the top passenger side of the engine, but I can't tell exactly which device causes it.

Anyone have any ideas?

Thanks.

 

My 97 250 5.4l did something like this. It kind of sounded like a buzzer, and from the inside it seemed to come from the dash. Atually thought it was in the radio. Turned out to be the PCV valve. You can hold your hand on it and it may even stop.