Ok first of all I'm new to this forum and to diesel. I recently bought a 2005 F-250 SD 6.0 Powerstoke diesel, for about 2 months now Ive been hearing a "screeching" sound when I accelerate and just at a crusin speed(35-40). So I took it to a mechanic and they told me its a belt and fed me the b.s. card. So they replaced it and called to say that it still makes the noise. Now they say it may be the EGR, but I know that was replaced before I bought the truck. So I took the truck home today and decided to punch it, when I did I heard a loud pop then whistling when accelerating and no more boost in turbo. So I hope this isn't an expensive problem. Can anyone tell me what's up?