[Frank Messina]

You don't indicate what you have for a distributor so I'll just throw this out there. I had a similar no-start hot problem with my pickup many years ago. Started okay cold but no go when hot. Traced it to a faulty pickup coil in the distributor that created an open when hot. Once it cooled off it would fire up again. I doubt turning off the fuel pump has anything to do with it anymore than slamming the glove box or twisting the gas cap. FWIW
Frank