[Maximumrisk]

This afternoon I was going to go out, I started the car, put it in reverse and was backing out when suddenly the car started to hesitate and shuttted off. I tried to start it a couple of times, it would turn but not start. I checked for spark and there was, but when I looked at my fuel pressure gauge the reading was very low (about 14PSI). So I went back into the car and tried to listen for the fuel pump to start, and it did but it did not sound like the tipical mustang fuel pump sound; it was not a whining sound, but it did make a sound. I checked the relays and they were good.
Last week I had the car tuned, so I decided to check the computer just for the hell of it. I moved the connectors a bit, put it all back in its place, tried to start the car and It started right up, checked the fuel pressure and it was back to normal. And the fuel pump made its normal whining sound.
My question is: Does the fuel pump alert you when it is going bad?
because as far as I know when it goes bad the car would not start at all.
Or does it start to do this before going out?
Or is there a connection between the computer and the fuel pump? Is there any chance that maybe my tunner did not reconnect the computer properlly and that it maybe became loose after a while?
your opinions are greatly appreciated.

[GhostDog 5.0]

If you put the keys up , down up down repeatively does it change the fuel pressure? How is the fuel filter? If you press the gas after you turn it on, does it stay on?

[Maximumrisk]

the fuel filter was replaced the same day the car had its chip burned, a little over a week ago. When the car started, I accelerated it and it all was normal, like nothing had happened. As a matter of fact, I don't even have to accelerate it for it to stay on.
I'll check the fuel pressure when opening the switch...