Every once in a while i will get this code
P0137-HO2S Circuit Low Voltage Bank 1 Sensor 2

and then it will just disappear.
I think it is related to me getting into the higher rpms, because i think i only get it when im driving real fast. If i drive normal it seems like it goes away.

Which leads me to believe the code has something to do with my car running lean in the higher rpms.
Could this be why i am getting this code every so often? because i am running lean?
because the car drives fine no shaking, hesitation, or anything like that.

 

Its set when the drivers side post cat O2 voltage is below 40MV. I know on some you can swap the sensor with the other side and see if the code follows telling you its a bad sensor. I am not sure of your model if thats possible.