New to the site so want to say thanks in advance for any help or info. I have a 2008 6.7 3500 quad cab with 142k on it I believe. bought the truck as is and not sure exactly what all has been done to it I tried contacting the previous owner to see what exactly has been modified or changed out but no response. from what I can tell by just looking it over it has cold air intake. straight exhaust 4inch with all the factory sensors still installed, egr block off plates. egr servo on passenger side is zip tied up and still plugged in, something else is the same zip tied up on drivers side and wires still connected. I noticed it does have arp head studs installed and looks to have had a h&s tuner on it at one time as the pyro cable was left in engine bay area but I have no tuner for the truck at all now. I have owned it since it had 117k on truck. it ran fine for me for except maybe 3 times it fell on its face while under hard acceleration and the lighting bolt light came on the dash display. by the way truck is a manual tranny and 4wd. factory turbo as well. my problem is recently for the past month I started traveling from rock hill sc to Hilton head area for work which is a 3.5 hour trip while doing so the truck will randomly lose power and will not even overtake traffic or accelerate. during this time the check engine light comes on throwing p000f, p0471, and p0489. perform service comes on the head unti and see dealer now appears as well along with service required. the truck will normally "roll coal" under hard accel without the turbo being spooled up but when the power loss occurs it does not emit any smoke out of tail pipe. I can hear the turbo screaming a loud whistle and the coolant temp will rise from 190ish to above 200. if I barely press throttle the truck will drive like normal and hold 60-70 mph but only if ground is flat and no load behind truck. if I press the pedal down any further is when all the above occurs. sometimes when this happens and I pull over the truck will come to a rough ideal and then shut off and when I go to start it again it takes many attempts before it fires up. if I clear codes there upon pulling over turn truck off and restart it, it will run normal again. sometimes it will run normal enough o get back up to speed within a mile and then lose power again and other times it will take an hour to act up. im completely lost of where to begin as money is tight and I don't want to go throwing it in the wrong places chasing something that is not the problem. any help is greatly appreciated. thanks again.