So i had this CEL for over a year never effected my car. O2 bank 2 code. So second O2 sensor messed up. Changed nothing with my engine or anything, didn't notice a thing. Now after I'm sitting at a light and it seems like my car wants to die. Idle isn't constant and varies a little a couple hundred rpms. 2 days ago I pulled up to park in two and I killed it somehow. Now my foot wasn't all the way down on the clutch but mostly. Any quick thoughts? I'm guessing I should replace the O2 first but what gets me is that its been like that since last year and nothing until now.

Rear O2 wouldn't cause that. Its only function is to monitor the catalytic converter.

Checking for vacuum leaks for air in the cooling system is a good place to start for idle problems.

Thats what I thought the cel couldn't have anything to do with it. Yeah I'll check for leaks thanks for the quick input.

Ya actually i have a ATX trans well did. And Both of mine were bad. the only time that i actually noticed a different idle was when i turned on ac...Look more towards ur vacuum on the manifold i think? Check your repair book for a stall...

Replace the o2 sensors, this might not be the stalling or idling problem but when you say it does not affect the engine your wrong. When you are running with an o2 sensor code you are running in open loop, this means your car will always be running off fuel maps set from the factory for cold starts. This also means that your fuel mileage will be affected because your car will always think its warming up and dump more fuel. So fix the o2 sensors and go from there.