Truck has 583K miles on it, through a rod through the side of the block. Contacted Ford dealership and got a new engine, included with engine was hpop, wp, injectors, cam sensor,icp sensor,ipr,turbo, pretty much everything. Installed a new engine wiring harness. Started truck up, it is misfiring, put into gear, drops down to about 500rpm. Misfiring still. Pulled codes, got a P1274, tested wiring from IDM to injectors, they ohmed out fine. Installed new IDM. Still same problem, buzz test passed, KOER passed fine. Im out of ideas. I have no codes, but misfiring under light load and low throttle. Truck going down road runs great, but only 8PSI of boost. Everything is stock, except for 4" exhaust. Im out of ideas here. What do you guys think?