About 2 weeks ago I was on the highway just cruising along, trailer in tow. Then BAM! The truck lost all power almost like it was running on three cylinders, no CEL or dummy lights. I pulled over and shut the truck off. After a quick look under the hood I attempted to start it again. It started but ran as if it was on 3 cylinders, and was smoking from the PVC hose which has a filter due to the aftermarket air filter setup. The only code that has been constant since I was towed home is P00C6. I have checked and replaced a bunch. Here is the list: Spark plugs, wires, drained tank, new gas, new fuel pump, Fuel pump control module, checked fuel pump fuses, relays, and wiring. Camshaft actuator solenoid magnet, camshaft positioning sensor, Fuel pressure sensor, fuel rail pressure sensor. I have cleaned the upper intake, throttle body and the intake ports the best I can. I don't know what else to do other than the high pressure pump. I just dont want to spend that kind of money for it not to be the issue. Fuel pressure is definitely lower than commanded it really never goes above 1100psi at the rail. Does anyone have any input or ideas? I'm at a roadblock and I can use some help . Thanks in advance.