My 95 Roadmaster stalls when driving. No discernible sounds coming from engine prior to stall, just complete shutdown. Sometimes I am able to restart the car immediately, sometimes not. I have taken the car to a mechanic twice and they have been unable to diagnose the problem
Car stalls when driving on 1995 Buick Roadmaster
The problem, being intermittent, is hard to diagnose. But hopefully you will be able to catch it in the act one day. I would anticipate it would be a lack of spark or fuel pressure that occurs.