Stalls for no reason?

Last year just before I put my 1984 Carrera 3.2 into winter hibernation I drove 150 miles or so in a day. The car ran beautifully for most of the time. Suddenly while doing a constant 70-75 mph in 5th the car stalled. Just like that, no hickups no warnings it just died. It would start and then run perfectly all the way home.

I have no idea why it stalled and it runs great now that I've taken it out of winter hibernation after 6 months of standing still.

So I wonder if it could be the fuel pump relay? Maybe it's loose in its socket? Anyway I'd like to know where the fuel pump relay is located even if you guys don't think that's where I'm going to find the fault.

Could it be the DME relay? If it was faulty the car wouldn't run at all would it - same goes for the fuel pump relay btw? Can a loose fit in the socket cause the car to stall?

Suggestions are welcome since I don't know when is the next time this problem will come up....

Bump.