@db4690 … no, mine isn’t that fancy. It can’t record, neither can it display max/min/avg.
@Tester … yes, I’ve seen that done on a U2 vdo. Seems like it would prove the O2 sensor is working or not. Still, I prefer to see how it works on the car rather than on the bench, but your method may be my best option sans purchasing a better volt meter.