Rattling and an observation.

[PETARDED]

Popped the hood as I was curious about this cold engine temp rattle that I have, it appears that the accessory pulley is vibrating left to right. There is a ton of "mechanical noise" coming from the front of the car when it is cold, but when I got to work, the idle was "Mechanically quieter", but the accessory pulley was still vibrating. Is this normal?

[DownhillA4]

I've noticed this as well over the past few cold mornings. Interested to see what people say about this.