Question

P0171 Ford - I don't see the specific (Explorer-Sport Trac-2001) model of my truck listed on your "specific Ford models" list. Are the causes different model by model?

Answer 1

Most of the ford model are the same

https://www.autocodes.com/p0171_ford.html

start by checking for intake leaks, and maybe clean the mass air flow sensor with mass air flow sensor cleaner.

if problem is still there oxygen sensor on bank 1 sensor 1 will have to be check nad maybe fuel pressure.