MAF Reading 0.01 at LB/S

Hello there, before I begin explain, please understand my English is not good, its my second language and I don't speak it often. Anyway,

My 2001 Toyota Corolla have P0171 code, too lean bank system 1, I've been gone through checking the fuel, Long Term Fuel 1 reads high percentage 28% while my MAF reads 0.01 to 0.02 LB/S not grams per second or Hertz. Is that normal? Although the vacuum intake doesn't suction anything, it's possible to have leak or vacuum canister failure. Let me know if you can help me out thanks!