380 SE stalling

[mook]

My '81 380 SE has started stalling at infrequent times. There is no warning, the engine just stops. Usually at stop lights, but sometimes just going down the road. I suspect it is the fuel pump relay. Is there a way to test the circuits to determine if the problem is with the relay or some other problem with current not getting to the relay? I have checked the wiring at the fuel pump and the ignition switch and I can't make the system malfunction in the driveway. Any ideas??