My SES light came on so went to auto zone and they said it was my o2 sensor, they didnt tell me which one. So A day passes and the SES light goes out but the car still feels sloooow, but now i dont have any way of finding out which one it is. And how hard are they to replace?

 

Next time write down the code, I did it, and it shows which bank and the symptom. It was just a glitch, as the ses lite went out after 10 turn keys.

 

If it is an actual problem, then the code will be thrown again.
If it doesn't light up again, then be happy that you don't have to pay to get it fixed.

 

This is correct. My SES has been going on and off for months now. As soon as the weather warms up I'm going to try this:

Way to revive your bad O2 sensors.