code 1131 and 1151

Both banks are showing "lean" which would lead me to believe that there is an air leak somewhere still -- after the Mass Air Flow Sensor and into the intake manifold. Check the PCV system to ensure there are no leaks in the PCV hose. You could have an air inlet restriction also. Don't be thinking of oxygen sensor replacement -- the fact that both banks are showing codes for the same concern leads me to believe there is an overall problem likely with air intake. Not sure why you replaced all those parts before, for the same concern? You said "now it has (codes)", did it not have those codes and symptom before?