QX4 P0171 and P0174

[daroutt]

I've been getting these two error codes and need some help on figuring this bug out. First was the P0171 "Bank 1 too lean". A local NAPA guy who sounded like he knew something about Nissans said it sounds like the MAF sensor and to clean the MAF before replacing it and get a new airfilter. Did that and the P0171 went away for a few days. Now I get the P0174 "Bank 2 too lean". Can anyone tell me is the MAF the problem, is it on the fritz, or is it something else? It was suggested by another NICO member to have the ECM reflashed because I just changed both after cat 02 sensors. Will this reflash help the current error code problem?

[Power_Dr]

I was getting the P0171 code and I tried to clean the MAF and then the code came back. I replaced the MAF 5 days ago, and today the light came back on. I haven't read the code yet but I am thinking it is the P0171 again. I am wondering if it is an o2 sensor. I was monitoring the o2 sensor voltage at idle and the bank 1 sensor 2 voltage was at 200 mV and the others were around 800 mV, does anyone know what the voltage is supposed to be at idle and 2000 rpms on the o2 sensors.