Lexus Repair: P0171, air flow sensor, o2 sensors

Question
I have diagnosed the light, and found it to be problem P0171, System too lean.

What does this mean?  Cannot seem to find what needs to be done.

thanks for your help.

Answer
Hello, After the code is pulled is when the work starts. You will need to inspect the O2 sensors, air flow sensor and injectors. I would start with the O2 sensors and air flow sensor. What it means is that the vehicle is not getting enough fuel. Any quality Lexus repair person should not have a problem checking this. Thanks