confused with my 96 grand prix, fuel and possibly power loss

a few weeks ago my grand prix shut off, it chugged and died, it sounded exactly like it was dying for fuel, the fuel pump was brand new, so i tryed a few things first, i changed the fuel pump relay- $18, worked better but still wouldnt run,
while at car quest a guy suggested the crank sensor might shut off power to the fuel pump if the crank sensor was bad.
i tapped on the fuel tank and the pump still wouldnt turn on. i pulled up the carpet in the back seat to see if the fuel pump was under the seat, all there was only two wires going to the trunk and back under the floor, (the fuel pump doesnt poke up through the floor like some cars) but it was very damp under there so i thought maybe a wire to the fuel pump was shorted out.

i had it towed up to the high school where we hooked it up to a diagnostic computer, nothing showed, up the car didnt know it was broke. without changing anything more it started up and ran for three days, then it died again, i got it towed back up to the school- and it started on the back of the tow truck, and i backed it off (its getting frustating at this point) we put it on the computer again nothing looked wrong, checked fuel pressure and changed the fuel filter- $9, it ran for a week, shut off once (i waited two minutes and it started up again, and ran for two more days),
- so i took it to the mechanic down the road and changed the crank sensor, i also got him to change the plugs and plug wires. when i got the car back i drove about 40 km, about a three hour stop half way in between, i filled the car with gas at the store went to start the car, no fuel pump, it wouldnt turn on (no whirring sound), so after fiddling with some wires, beating on the tank, we pushed it out of the way.

i talked to some mechanics, and got some ideas to try.
- get rid of the corrosion on the relay box wires
- check for fire
- check for rust or corrosion on the module
- and check for a check engine light
before doing anything i tried to start the car again, no fuel pump, tried three times. so i tryed the easiest first, the check engine light, so i took the third plug wire from the passenger side off the distributer (just picked it randomly) then i turned the car to accessory, no check engine light, but the fuel pump turned on, so i kept going and started the car, it started fine (missing one cylinder of course) so i plugged the plug wire back in and tried again the car started up fine and i have been driving it for two days now.

i am very confused on this one, i have come up with two scenarios myself, but im just guessing.
- the plug wire i dettached was a loose one, after driving as far as i did, with no check engine ligt i had no way of knowing and the computer shut down the fuel pump, and when i pulled off the wire it reset the changes and restored power to the fuel pump. this one is a long shot to think that the first wire that i pulled off was the right one.

- the module was getting a bad connection and the same thing happened, when i pulled the plug wire off the computer rest and allowed power back to the fuel pump, if thats true then it shouldnt have driven me home, once the module heated up, it should have shut down again, i put on forty kms today alone, its still working.