I have a Nissan Maxima and all four sensors were just replaced, and now I have codes P1168 and P1051 now.

Question

What could have cause this all of a sudden? What needs to be or can be done to fix it?

Answer 1

Try clearing the mixture ratio self learning control data. Instruction here: http://nissanhelp.com/diy/maxima/projects/nissan_maxima_clear_self_learning.php

If the problem persist and there are no intakes or exhaust leaks,, you may have to have the dealer reprogram the ECM for you.