turns off

The repair shop looked at pending and "hard" codes stored in your truck's computer. A professional grade scan tool has the capabilities to look at the sensor values for a lot of key engine sensors with out having to do intrusive testing at each sensor, but again the tool and its information is only as good as the person looking at the raw information. You need to see what you are loosing fuel or spark. I tape a fuel gauge onto the windscreen and go for a drive, I also tap into key power supplies to see where you loose voltage or signal. You have to sit down with a wiring diagram for power train management and see which wires to attach a voltmeter of oscilloscope and go for a drive and see what signal fails.