No communication?

Truck shut off while driving after passing another car. Passed the car left off gas pedal and truck shut off. Will not start. No check engine light with key on, engine control unit won't communicate. Engine will crank but has no spark or fuel. Immobilizer light is off when key is in ignition. Checked all sensors and components on 5v signal and all appear okay. After siting disconnected for a few days I reconnected the ECU and it communicated for few minutes but wouldn't start. Fault was stored in ECU for internal module failure. Replaced the ECU but the truck still won't start. No communication possible with the replacement ECU, no check engine light with key on and no fuel or spark. I tried using a re-manufactured ECU that was programmed with my VIN, I also tried using a junkyard ECU when the re-manufactured unit wouldn't communicate. I have tried all 3 of the keys I have for the truck. The voltage to the ECU is good as is the ground. I'm out of ideas a this point and hoping you can give me a new direction to chase. I also tried to do the ECU "handshake" with the junkyard module installed by shorting pins 4 and 13 but it only turned on the TPM light and didn't seem to do anything else.