Ford Repair: 99 ford exploer, mass airflow sensors, vacuum leaks

Question
i was wondering what it could be when the system is to lean and the OBD 2 reader says bank one and bank two is two lean and also when i was driving it one day it just died on me and now it wont stay running but when i go out in the morning it will run but i drive it for a while and it stalls out on me and wont start back up

Answer
lean codes are usually caused by vacuum leaks although faulty o2 sensors-dirty throttle bores-mass airflow sensors and sticking idle control motors also cause this-i would check for vacuum leaks-clean throttle bore and iac motor-check mass airflow to see if it is dirty also. it has two filaments that get dirt on them which makes the engine think it is lean.