I replaced them because on another thread, a guy told me that error (P0053) was the one he was getting, and he solved it by replacing the o2 sensors.
http://www.elcovaforums.com/forums/s...625#post547625
I will try what you said, and put the old one in bank2 and see if I only get the lean code on bank 1.
If that happens, I will put the old sensors back in, and should get the P0053 again. If that happens, what should I do to solve the o2 heater code?