One of the most important things to do to these cars is to have a refurbished or new RCM (relay control module) installed in your car. We have another owner that can refurbish them within about a week turnaround time for about 1/3rd the cost of a new one. These modules have mechanical relays that tend to fail (it's a 20 year old car now) he can fix it better than new. A failing RCM will cause the exact symptoms you described.It takes less than 5 minutes to replace it on your car. Most owners change it themselves.
The second item to replace is the crankshaft sensor. Buy only Bosch brand sensors.