what could b possiblecause for lean bank 1 & lean bank 2

Question

2003 ford f-150 code po171& po174
lean system bank 1 & lean system bank 2
what could b cause

Answer 1

P0171 and P0174 Lean fuel system

In most cases its the fuel pressure that causes this , This can also be the MAF (mass airflow) no properly reporting due to contamination where a MAF cleaning resolves the condition.Vacuum leaks can also cause this especially at the PCV hose and sometimes at the brake booster hose.