3800 cuts off

95 3800 is cutting off intermittently. Mostly right after started but has done it a few times while going down the road. Acts like the key was cycled off and on. No codes stored and stays running if you are driving but the run timer is back to zero. Starts right back up if it's at idle. Replaced the crank sensor about 2 years ago. Earlier this year the ses light would flicker rapidly at times on the first start and wouldn't run. Cycle the key a time or 2 and all returned to normal and started right up. Don't know if the PCM is causing it or not. Any ideas?

..there have been several cases where the ignition switch ...was the problem... I would test with a light or voltmeter connected real time on ignition circuit (pink on this '93 diagram) served by the switch to verify voltage condition when it fails...
www.avigex.ca/xport/ignitionkey.jpg