1999 Ford Crown Victoria Pulley

I've replaced both the tensioner and the Idler pulley already. Checked the power steering fluid, which is full. The water pump doesn't move when I push or pull on it, and it's not leaking water. The only thing that I've noticed is that you can push and pull the pulley for the power steering pump maybe 1/32 of an inch. And I wouldn't believe that would cause that much of a noise. I replaced the belt since the last posting, but I'm not sure if that really fixed the problem even though the noise has gone away. I replaced the belt because the back end (closest to the engine) Was frayed and pretty well destroyed. Thanks for the info though.

After I replaced the belt, the noise went away. Though yesterday as I was driving around it would start making the same noise again every once in a while. It would go away after a short while though. Every time the noise starts it's as if there is a pull on the engine. You can watch the voltage go down from the alternator. I'm not sure that I've fixed the problem correctly or not as I can't tell where it's coming from. Usually by the time I get the hood popped to check, the noise is gone.

I've put a used alternator already on it, and the tensioner is brand new, i'm sure that it is good. We took it out for a longer drive tonight and it seems that at highway speeds, it's fine. But as soon as you slow down, say to around 45mph, the noise starts up again. Also, when sitting in park, the noise persists until you rev the engine up, at higher rpm, the noise goes away. I am going to try to find some belt treatment spray, to see if that will do anything about it. Still unsure of what the problem really is.