1995 oldsmobile delta 88 stops running

oldsmobile

#1

The car will start & drive for approx 10-20 mins then die. A relay on the firewall “chatters” and the electrical seems to be interupted. After it sits for a while it will start & run again. There is no thermostat in place (I know this is not optimal) so the engine temp never gets above 150. The fuel pump keeps pressure. So it must be some type of electrical issue. Any HELP!?