Weird engine sound when cold or reving at idle

I'm confused with this new engine sound that seems to have appeared out of no where. I have a 2002 GT 5 spd. The first start of the day when my engine is cold and i drive off, which ever gear i'm in if i take it higher than 2K RPM's, i get this wierd rattling/vibration sound from the engine compartment. Its really hard to describe the sound. Its kind of like a metal to metal rattling vibration. Like say if you had a fan with metal blades and while it was running you barely touched another piece of metal to it so it would make a rattling/vibration sound. It is only there when the engine is cold and only when i rev past 2K and it stays there no matter how high I rev. Although once i get to like 3500K the exhaust and engine is so loud it drowns out the sound of the rattling.

New thing today i noticed is that this same sound is kind of there when i am at a stop light in neutral and i rev the engine to the same rpms. This happens even if my engine is warm. It makes almost the same rattling/vibration sound. It sounds like its coming from under the hood on the passanger side. I dont know if this is the same exact sound but it sounds really similar.

Anybody have this or know WTF i am talking about? Thanks guys.

AdRock:

Thats It exactly. So I have this "death rattle" in my car. I did a search and found some info but not enough on it. Can anybody summarize or give me a link with info. Is it bad for the car, or do most of them have it and I shouldnt worry about it?

Thanks Trinity.

Has anybody had this SSM done thru ford and did it help to get rid of the death rattle?