Squealing noise

Before you change the cam position sensor, check simple things first. Your vehicle has a serpintine belt that drives the accessories (water pump, alternator, A/C, power steering etc). They go tend to go bad and "glaze" after a while. I would try popping that off, starting the truck for a few seconds and listen to see if the squealing is still there.

Don't allow the truck to run too long without that belt off though, just a few seconds. Long enough to see if the squealing went away. I hope this helps.