I want to ask if there a way to check the O2 sensor in real time while the motors running to see if its working or not?

I know voltage fluctuates with rising temperature so if I back probe the voltage wire while the cars running what should I see? What's the range of voltage put out by an O2 on a 84 5.0?

That's after I run a new wire from the connector to the O2. I still have to find a better path that keeps the wire away from the back of the motor