About a month ago my truck started acting like it has a speed limiter in it. I hit 80mph it instantly leveled out and would not accelerate " truck will run 100+" i let off the throttle hit it again it seemed fine. My average trip with it is 800 miles. Next trip it constantly lost power soon as I let off the throttle and hit it again the turbo spools up till around 2100 to 2500 rpms. When it looses power I hear a pahchewwwww like air discharging. On my scanner my fuel sensor shows 40k to 60k of pressure when it releases turbo pressure it drops to around 5k pressure... any ideas? The small rubber hose on the bottom of the turbo had split when this started its about 6 inches Iong replaced it. Codes have said over boost and under boost at the same time. Truck has 420k miles but only 45k on jasper motor... probly stock turbo not sure. In the daytime you see no smoke at night in headlights behind you see alot when its acting up

 

no one has any ideas what this might be..... ?