Fuel Pump Issue

[KFoster]

I know this has been discussed in several threads, but I wanted to outline my issue to see if it relates to one I read about a loose wire at the top of the tank or something else. I have used the threads to help. Car ran great a couple weeks ago, then last Friday it would not crank. It would fire after the initial start, then stop after a few seconds. Strange to me that the fuel pumps could work one day then not the next. This has not been an issue and there has been no recent work performed on the car. New battery a few months ago, but fine since and it has been driven many times since then. Car will start for about two to three seconds. Fuses are good and I swapped relays around after finally figuring out where they are. I checked fuses on the side of the dash and under the dash. Horn hasn't worked since I bought it, so swapped the interior light relay with the fuel pump relay with no change. Using the sticky thread, I checked the fuel pump with the underhood connector. It would show 6.5ohm for a split second, then .5 ohm. Repeated this several times. Pumps did not kick on, no pressure. Car turns over and will fire, but only run for a couple of seconds. Very repeatable. No pressure in the rails. I haven't put a gauge on it, but you can push the valve and some fuel runs out but no pressure behind it. The connector block behind the battery looks fine, wires feel tight on it. So, several threads out there have contributed to my investigation. I believe the fuses and relays to be good. Will fire, but not stay running. Anybody have this particular issue. I could see a loose wire causing it, but how does it sit for a week and a wire become loose with no intermittent trouble prior. I have not checked the wiring at the tank nor see if power is making it there. That will be next though. Any other thoughts. Could the pumps die overnight like that? I really thought it would be a sticking relay. My experience is they can stick on. I hate electrical issues. Any help is appreciated.