Valve cover causing lean?

[raider03]

First off, excited to join the group with my 2001 x5 3.0 w/108K miles...

So I have been getting P0171 & P0174 Lean on both banks. First I cleaned the MAF and no change. Checked visually all vacuum hoses all seem ok no cracks. My O2 voltages are really low, lower than .1volts. thinking it could be O2 sensors but many is telling me is air leak, if true it most likely going to be a big leak because of the O2 voltages being so low.

So last week took the car to a bmw dealer and spoke to the tech, according to him there is a crack in the valve cover close near spark plugs #3 & #6. Forgot to ask him how he verified because when I took a look without taking the valve cover off I do not see any visual cracks. As you all knw the valve cover is around $300 bucks. Wondering if it is indeed cracked or is it just the valve cover gaskets that need replacing?

Another thing I was wondering, what are normal MAF readings at idle? I am getting 2.4 - 3.6 grams/sec at idle, Is it that my MAF is on its way out?

Would really appreciate any kind of help and feedback. Wanting to fix this asap, as my mpg is suffering and going thru tank refills fast. Thanks