1999 Buick Regal stalls without warning

This car has the 3.8 l engine. It has started stalling without any signs that anything is wrong. It can stall at any time - braking or accelerating, cold or hot. Engine just stops dead and lights/radio remain on. No engine codes result from this. Normally starts right up and runs great for the rest of that trip. The last time when restarting it did nothing until about my fifth try to start it again.

I don’t know if this is related but occasionally the traction control on this car acts up where lights like Trac Off, ABS Brakes, Check Engine Soon come on. In this case if I shut the car off and restart everything is fine. Lately I notice this quirk happening with more regularity making me wonder if it’s related to the engine stalling problem.

There may be an intermittent power connection or problem with the ignition system. The ignition switch could be the trouble also.

There may be just a momentary loss of electrical power which stalls the engine. Finding that connection, whether it be wire to wire connection, wire to switch connection, wire to component connection, is the challenge.
First place: battery. Disconnect the battery cables and clean them with a file, a knife, wire brush, or sand paper. Sand (or wire brush) the battery posts. Apply petrolatum jelly to the battery cable ends, and battery posts, and re-attach. Check the large wire attached to the alternator. It has 12 volts, always. The nut should be snug.
Prepare for the next time the engine stalls: carry a spray can of Engine Starter (or, similar) and a test spark plug which clamps to the engine. Test spark plugs are available at auto parts stores.
When it stalls, and doesn’t re-start on the first attempt, use the test spark plug, and, then, the Starter Spray. Take notes of symptoms and the results of the re-start attempts, and let us know.
If the check engine light is on, let an auto parts store read the trouble code for you (free), and bring the code(s) here.