2004 6.0 powerstroke need help please
 

Hi guys I just bought a 2004 power stroke no mods just head studded. I was driveingbit down the road an midde throttle it loses power an the turbo sounds like its blowing off, like a ricer. The truck will do it down the high way some times, or even cruzing down the road at 45. Any idea's the truck has 160, 000 miles. We checked the turbo its spooling. An theres no shaft play. Any help would be great thanks.. chris