thx fishmech

Look for connector under floor board on left side of truck. Put in jumper from A to D and turn switch on. Watch engine light blink. There should be three consecutive codes of 112, then any engine codes should come up. A couple of things you can also check. Make sure alternator is operating correctly. Should be charging about 14.2 to 14.5 volts. Make sure radiator is full. Look at oil pressure sender under the distributor. Any oil leaking may be signs of the sensor failing. When pressure drops to low, engine will shut down.