I rear o2 does not control the afr, The front o2 does. Your car needs to be tuned correctly to your modifications. Speak with professionals before making decisions on your car, there is a lot of misleading advice in the blogs.
After a long pain staking process I found my issue and fixed it. After I installed everything the way I ran my maf sensor plug was very tight and after awhile of engine movement and heat yadayada the wire had a lot of tension a pulled out slightly. I open the connector and pushed the wires back...