With CONSULT-II

Start engine and warm it up to normal operating temperature.
Select "SELF-LEARNING CONT" in "WORK SUPPORT" mode with CONSULT-II.
Clear the self-learning control coefficient by touching "CLEAR" or "START".
Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?

Is it difficult to start engine?

Fig 1: CONSULT-II Display Screen
Courtesy of NISSAN MOTOR CO., U.S.A.