What can cause Codes P0171 and P0174 in Mazda 6 Year 2004 model

Question

Mazda 6 codes P0191 and P0194

Answer 1

P0171 Fuel trim too lean (RH)

P0174 Fuel trim too lean (LH)

Reason for DTC , more air to fuel ratio,MAF (mass airflow) malfunction ,fuel pressure below specification,varaible valve control system, vacuum leaks causing lean condtion,

Diagnosis area, Perform a MAF cleaning, with a throttle body,inspect for false air such as the PCV valve,  vacuum hose disconnected or ruptured, and fuel pressure specification is 63-73 psi at idle. Purge solenoid. not holding causing lean condition

Related TSB : 01-052/06

At one time the purge solenoid was warrantied which caused p0171 and p0174 ,what was replaced was the purge solenoid and purge hose, which resolved the problem.The purge should be the first to be inspected for proper operation ,