What makes a chirping sound on my '01 Ford Mustang?

I have changed the pulley barron, serpentine belt, the tension pulley,and the water pump.Was told the alternator was good. What next?
What makes a chirping sound on my '01 Ford Mustang?
If it is the 3.8L V-6, check the synchronizer. The cam sensor is mounted to the top of it, and the synchronizers on those are bad about the bushing failing. It sounds exactly like a bad belt or pulley. You can actually push the synchro very slightly with a screwdriver, and one way will make it louder, the other way stops the chirp. Then you know for sure that's the cause.

If it is a V-8, then just keep hunting at the accessory drive.
What makes a chirping sound on my '01 Ford Mustang?
DID YOU CHECK THE IDLER PULLEY ALSO?
i don't know exactly what chirping but mine made a really high pitched chirp. i thought it was coming from behind the steering wheel but a lot of trial led me to find if i smack the part of the roof between the visors and above the rear view mirror hard enough the chirping stops. don't know why and it might not be the same thing but try it. haha
you have a bird trapped and he chirps when the engine starts...lol Does it go away when the engine warms up?



Is the belt tight? Spray some belt dressing or wd40 on it engine off...close hood and start so stuff does not fly on your paint...and see if that helps.