I have a 4.6 liter F-150 and when i start it up in the morning it chirps like a bird, and it is extremely annoying, but then after I shut it off and then start it up again later on it is considerable quiter and you cant hear it as easy, any idea's on what it might be, thanks.

 

Did you check your belts and oil? Can you pinpoint the area of the engine bay where it's coming from?

 

To eliminate a internal chirp take the serp belt off and do a cold start. If no chirp its probably a idler pulley or the tensioner.

 

Sounds like my wifes 96 5.0, do as torkum suggested, if noise is present listen to the cam sensor with a probe. Sensor is hard to find, below EGR, coming out of engine at an angle between alternator and EGR. With sensor removed from base, I flooded the shaft area with WD-40 trying to get to where the shaft comes out of housing. Been OK for a couple of weeks, I know I'll have to go further if chirping returns. Takes a special tool for alignment if entire housing and shaft is removed. Sensor is no issue at all, two small screws and only goes one way.