Please help with check engine light and code P0171 lean condition....

[keng]

Hey guys I am having trouble with my 1998 explorer 5-speed. My check engine light came on and I ran a dianostic and it came back with a code P0171 or Po171 which are system o lean. What could be causing this?
What should I check.

 

[Blee1099]

Please don't post your question in multiple areas.

 

[Glacier991]

Initially you need to look for vacuum leaks. Check out TSB 00M12 (search)