Check into your ignition switch, I had a 95 that was doing the same thing and it would run for a while then not start sometimes. I replaced the PCM twice as they sometimes go $400.00 each. Replaced the ignition switch it was $130.00 or so, took about 1 1/2 hours to do it and ran fine ever since.
The switch is reasonably easy to do, but you will need a steering wheel puller, which you can buy or rent.