Bank 1 oxygen sensor location

Which sensor? There are two on Bank 1, upstream (Bank 1 Sensor 1) and downstream (Bank 1 Sensor 2).
What code or reason makes you think you have to change the sensor? What problem are you having? I ask because although the sensors can go bad 99% of the time a code does not mean "change this part".

Those codes can pop up for a lot of other problems is why I asked. Most of the parts stores see a code and immediately say, "oh that is part XXXX", but the codes very seldom point to a part.

Take a common P0301 code for instance. That means "misfire on cylinder number 1"
The parts store is going to tell you, replace the plugs and wires (or coil if a coil on plug system). Could that be the problem?
Yep, but it could also be a bad valve(s) in the head, worn cam lobe(s), low compression, plugged or leaking fuel injector, bad PCM, bad ignition module or a bad head gasket.
Thing is that two tests can eliminate or find most of those easily. Relative cranking compression test, and a simple scope test of the ignition in that cylinder.

If they did not erase the code it should still be in the history codes, they should be able to get that for you if you wanted. My bet is that, as the light went off, you have a wiring issue to the sensor, either a wire rubbed or melted or the connector is corroded. That is because if it was the internal sensor itself, the light would still be on, they do not repair themselves.
So look over the wiring from all the sensors and make sure it is not damaged or corroded.

Hi,

I think I can help even though I am not Steve. We are not all answering questions at the same time so I will just add my 2 cents.

Since this just happened after the vehicle was topped off, I suspect the purge valve is damaged and the vapor canister most likely has fuel in it.

I attached the info about this code but normally this is just a by product because when the purge sticks open it is dumping too much fuel and the vehicle will stumble and run really poorly.

I would suggest starting with removing the purge solenoid/valve and opening it up to see if there is charcoal residue in it.

What happens is when you top off the tank (put more fuel in when the nozzle shuts off the first time) or fill the tank with the engine running, the evaporative emission system will pull the raw fuel into the canister and soak the charcoal that is in there. This will cause the charcoal to break down and go into the purge solenoid when it opens. When this happens it causes it to stick which allows too much fuel vapor into the engine. This makes it run too rich which is why you smell the fuel and get the running poor condition. Then the o2 sensor sees that the converter is not reducing the NOX enough because of all the excess fuel and it sets the inefficiency codes.

Many people condemn the sensors, then the converter and then when it turns on again they don't understand why.

I would start with at least inspecting these components (canister and purge) before replacing any o2 sensors or converters. If they check out ok then it is most likely the down stream sensor even though the upstream can cause this as well. I would suggest just swapping them side to side one at a time and seeing if the code follows. If it does then you know which sensor it is. If it doesn't then it is most likely the converter.

Steve is on here pretty frequently so I am sure he can fill in anything that I missed. Thanks.

That covers 99% of it. One item I'll add is that you can do a quick test with a non contact thermometer on the converter to see if it is at least trying to work. On that vintage vehicle you should see at least a 30 degree difference in temperature between the inlet and outlet. Usually more being it's an older system. What you don't want to see is an outlet temperature 200 degrees or more higher than the inlet temperature. That would mean there is extra fuel in the exhaust and that can destroy a converter in a very short time because it actually burns the rare elements off of the ceramics and can melt those as well if it gets hot enough. A quick clue that it is running that hot is a discolored or warped shell.

For some other tests on the converter itself there is this.
https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

If you have access to a scan tool that can show live data you can also look at the O2 sensor voltages, what you want to see would be the front S1 B1 and S1 B2 both switching fast as they regulate the fuel system and the rear sensor S2 B1 staying at a steady low voltage with just a minor change. If the rear sensor is reading the same as the front or close to it then it may already be too late.