Check Engine Light Codes

I Just picked up a 2001 XG300 a few days ago with only 90K miles.  car ran smooth and great.  After about a week of driving the check engine light came on, i checked the engine codes and found four.  PO174 System too Lean Bank 2 , PO171 System too lean Bank 1 , PO320 Ignition/Dist Engine Speed Input Ciruit Malfunction, P1159 Manufacurer Control. Fuel Air Metering.   .  any suggestions on what part to change?  any help would be greatly appreciated.
 
thanks
 
 

mass air flow sensor is no good. replace it.