Ford Repair: fuel too lean, mass air flow sensor, mass air flow

Question
I have a 2000 Ford Winstar 3.8 V6. The check engine light came on and we had Auto Zone run a check on it. They told me that the Mass Air Flow sensor Or Oxygen sensor needed to be replaced. I had the light turned off to see if would come back on and it did and this time they tell me the codes were PO171 & PO174 Fuel too lean but couldn't tell me what I need to do to repair the problem. They told me could be fuel pump, fuel filter, oxygen sensors or fuel injectors. What would you advise. Thanks Paul

Answer
Hello and thanks for the question...I'll try to help.
 What I would suggest to you is that you bring it in to a Ford garage. I hate to say it, but there are too many systems and conditions that can effect the vehicle and set these codes, and Autozone, isn't a good place to go for diagnostic help.
 Yes, the codes you got are for bank 1&2 running lean. What is causing that, I can't say, with out looking at the vehicle for testing. I wouldn't just go throwing parts at it in hopes of a cure.
Hope this helps,
Erik