Persistent P2C3d error when running tune

I have been having a persistent p2c3d-lambda probe before catalyst, line fault code when running the procede flex-fuel flash or Wedge's flash only. I do not get the code while on the stock tune. I also only seem to get it when I go WOT.



I tried replacing the bank one, front 02 sensor just a few days ago...it did not help. What else could be causing this?