no power to the injector or the coil after 20 minutes of running what can i check or fix
truck runs for 20 minutes then it stop Icheck the relay they work what can i do on 1990 Dodge D250
Possibly intermittent CKP Sensor. Check you Crankshaft position sensor wiring and connectors. This sensors input to the Powertrain Control module is what supplies the voltage to the ASD relay to power up the injectors and Ignition.
Sounds like a bad crankshaft position sensor. If it is cracked as the car warms up it expands causing a faulty reading.