94 Gt Won't Start..sometimes

My 94 GT will not start every now and then. It turns over just will not start. Usually after several tries it will start, but not always. The times I have been able to look at things before it started it had no fire. I have replaced the ignition module but after a few times starting and running it did not fire again. The biggest problem is it won't stay broke long enough to find out what is wrong. Once it starts it runs fine. Any ideas

I've already put in a new pump, regulator and relay. After some reading the hall effect sensor did come up a few times. Thank you for your input. I'll look there next, but I'm still open to any possibilities.