I'm having problems with my 03 6.0. When i take off from a dead stop the turbo takes maybe 5 seconds to start spooling and it runs great to about 60 mph and then it slowly runs out of boost. If I keep my foot in it at about 3000rpm the boost picks up again. The fuel filters were replaced 2000 miles ago the oil changed 1000 miles ago new AFE intake about 2000 miles ago. EGR is unplugged. If I try to stall (powerbrake) it takes any where from 25 to 30 seconds for the turbo to spool enough to spin the tires. Any help would be appreciated.