So the fixes turn out to be things that can wait a day or two until I get home: O2 sensor and EGR valve. I could drive home to South Carolina. That is now done.

On the way, I stopped for gas once, and when I started again the car was running very rough, and it was hard to keep it from stalling. The light did not come on again for quite some time, and as long as the light was not on, I had this rough performance. When I got back up to highway speed, the light came on and the performance was smoother. Periodically along the way, the light would go out, and the car would balk at the accellerator. In a few minutes, it would come on and performance would improve. Then it came on and stayed on until I was home.

Anybody able to throw light on this behavior? Is the ECU failing? Thanks.