Shuts off after driving fifteen to twenty minutes

Welcome to 2CarPros.

What you described sounds like a bad camshaft position sensor. When the start going bad, heat causes them to short internally. The camshaft position sensor on this vehicle is located in the distributor. See picture 1

Now, before we can conclude what is happening, I need to know if spark is lost to the plugs when the engine stalls and won't start. Here is a link that shows how it's done:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If you find there is spark and the vehicle won't start, see if it will start for a couple seconds using starting fluid. If it does, then the problem is fuel related.

Let me know what you find.

Take care,
Joe