Don't excited with throwing parts at the car, although sometimes this does work. It is possible it's a bad wiring connection, the few that I would look for is...........
right in the ignition switch/ connector. Might be that the IGN2 circuit (usually brown) dies some of the time. Could be through the bulkhead connector
Could be the distributor connector THAT IS A VERY LIKELY suspect as there is NO real current through that connector, only low level AC generated by the distirbutor pickup. So Work that in/ out several times, inspect for corrosion, and "feel" for tightness as you work it.
Also work the main ECU connector in/ out and inspect.
Make CERTAIN the ECU is grounded well.
