Q: Stalled while driving on highway now won't start turns over but won't start

Hello There, Stalling at high speeds as you describe can be related to many different things such as a random electrical failure or potentially a fuel supply issue. Since the truck does turn over and fire, this suggests you are still getting spark which would usually eliminate most of the electrical components leaving the fuel system as the most likely problem. This may be related to low fuel pressure, faulty or dirty fuel injectors, a faulty or dirty idle air control valve (this relays information about air intake to the computer which makes fuel adjustments), or potentially a faulty fuel pressure regulator or fuel pump. Fuel delivery problems will typically not allow the proper amount of fuel to be delivered to the cylinders which results in a lean fuel condition which can cause backfiring or simply cause the motor not to start as a result of fuel starvation. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.