Mine was the wires behind and underneath the alternator. They were somehow connected to the oil pressure sender light in the dash that would malfunction and light on randomly or flicker. Once I messed with the wires by the alternator, the light went away and I rarely lost power while driving after t...

Having near exact same issue. Only one fusebox by coolant reservoir. Haven't checked hall effect sensor. 1987 GLE. Cranks and cranks but won't turn over! Randomly starts when it wants to. Fuel pump is fine but for some reason doesn't pump when key is turned. This issue is such a PITA and already cos...