72 280se 4.5 stops running

Hi fellow enthusiasts;

I am new to this site so be kind. Here goes.

I have a 72 280se 4.5 that keeps stalling. It cranks over but won't restart. First time into the shop they tracked the problem to the EFI ECU ($$$ ouch!!) They replaced it and it quit the first day I got it back. Second time into the shop the car started when they went to try a diagnosis, so they played with the points and condenser. It took about 2 weeks the next time to quit and again started up after it was towed to the shop. They cleaned all the relays and conections having to do with fuel supply. The car is now in storage during the winter months and I am now leary about venturing off any distance from home.

A couple things that might help.
Cold or hot--doesn't matter
Can't here the fuel pump when key is turned on.

I think fuel pump. What do you think?
Any suggestions would be appreciated.

Jeff