Had the codes read and they show a misfire on cylinder 5, and both O2 sensors bad. I read the computer will adjust the fuel mixture to compensate for the misfire annd also read the upstream O2 sensor could cause the computer to adjust the fuel mix. How do I know which one to fix first? Is one problem possibly causing the other. Any insight would be appreciated

 

Yes, on could cause the other
Also, there are so many causes of a mis-fire
Usually if the O2 sensors are causing the mis-fire then it would happen to more than one cylinder
Or even random cylinders

First thing to do is ...
Verify mis-fire .. do a cylinder contribution test
Don't remember if the SF has coil over plugs (cop)?
If they do then move the cop to another cylinder and see if the misfire moves?
If it does then the cop is bad?
If not then try spark plugs?
Then it could be injectors or injector pulse?

Once had misfire due to the corrosion on the battery ground
A good mechanic cleans up all electrical terminals and grounds
O2 sensors .. should check the heater circuit and inspect wiring
Really need a good ODBII scanner to see the response of the O2 sensors

Good luck
Hope someone else comes along and can add more