One of the pulleys in my 99 2.8L is making noise when it's cold, then after a while the noise level would go down a little bit. But I am not sure how to diagnose which pulley is making that noise or does anyone know what my best bet on this would be?

Advice is appreciated.

 

I have the same issue right now. I have opened another tread waiting for replies from other friends here. It is your Idler Pully i am assuming. If this is your experience.

you start the car early morning. Then at the front of the engine you would here the noise coming. which is little bit irritating also. Then once you are inside and engine is running for a while, the noise is down but not completely gone.

Then i think it is the idler pully.

 

Verdict, did you mean the idler pully on timing belt? Thanks.

 

You can spray the serpentine belt with some lube to make sure its not coming from the serpenitne belt or one of its pulleys

 

Yeah just don't spray water on it because it tends to have the opposite effect.