Idle drop and weird grinding sound

[aaron34gtt]

Had to jump start my car after being away for 2 weeks, and when the car warmed up the idle would start dropping every 7ish seconds, and when it dropped the car would start shaking and a metal grinding sound was coming from the engine, sounds like as if you were slowly drilling through a piece of metal for about a second, and would then rise again. Never did this before, I could feel the grinding when the idle dropped when I put my hand on the intake piping.

Was too scared to drive it after that. Any ideas?

[Die$eL]

is it not a pulley bearing that is on its way out?