1987 Honda CRV electrical problem

1987 Honda CRV 4 cyl Automatic 120000 miles

My car shuts off while driving. My mechanic checked all wires and reports he cannot find anything. He reports it is very difficult to figure out an electical problem. He took out the alarm "box" and wires as its was very hot everytime the car was running. That IS NOT the problem because the problem is still happening. He thought it might be the key. That IS NOT the problem. I wondering if anyone has heard of this problem particularly in Honda CRV's because then we might know where to begin. It is like finding a needle in a haystack. Once the car shuts off, all you have to do is turn the key off and then back on and it runs again right away.