Starts and runs smoothly for 3 sec and then runs out of fuel. why?

Hello, So the ECU is shutting off the injectors to turn the engine off. But there are no codes? That is puzzling, however, the head gasket replacement is a good hint. Start with the throttle body connector, and make sure it is clean, and extra clean. Also, make sure the throttle body plate pivots freely when actuated, and there is no debris in the bore for the idle air control valve (IACV). To test the throttle position sensor, you can use a multi-meter, and see that the voltage changes when throttle pressure changes. Clean the connectors for all sensors that were unplugged, and make sure the relay for the injectors is not getting hot and failing (jumper). Let me know what happens, and I'll see what we can figure out.