You need a good, reputable, automotive electrical diagnostician.
Seriously.

I've done plenty of that type of work. I could probably find the problem in person, but it's very difficult over a forum. I'll give you what I can though.

I'm thinking that there is a weak electrical connection somewhere. Weak electrical connections get hot. As they get hot, the resistance goes up, it gets hotter and evetually it becomes intermitent. Tough to locate.

Finding this gremlin has to be done systematicly really, with a wiring diagram.
First, when it fails, it must be determined what exactly is failing. Is it ignition as in no spark? Is it no fuel flow? Is it a sudden drop in fuel pressure?

These are the things I don't know yet. Knowing that would help.

I'm not so sure what the hells your shop guys mean by ..."found that there is power to the fuel pump but no power from the fuel pump back to the computer.?????? Back to the computer??? That's a new one to me. This is where I need a wiring diagram, and my eyes and hands on the vehicle.