6.0 up to tricks

[Djanzen]

So i hooked up a scanner to the truck and checked the icp and the the pressure is in spec with no drop off after warm up. the ipr is at 24% at idle with warm oil. But this i noticed tonight when the engine acts up the exhaust temp goes through the roof 1100-1200f and boost goes to 7-8 psi with the engine max rpm with my foot to the floor of 2500rpm. it feels and sounds like the engine is under extreme load!. if i let the thottle return to idle the engine will stall and to restart will take about 45-90 seconds of cranking with it trying to start then it will slowly build rpms and take off. if i keep the thottle up enough to 1800- 2200rpm i can get it through one of these hiccups and it will start to run fine for about ten fifteen minutes. also when the scanner was hooked up we noticed that when the truck started to act up the exhaust back pressure went to 100psi.what the h-ll is going on!! does anyone had an engine do this?