Question

How do I fix the P0171 engine code on my 2002 Ford F150 Lariat 5.4L?

Answer 1

HI there

This code is for a lean fuel mixture on bank 1. This can be caused by several things, but only being on one bank does help narrow it down. Usually when it's only affecting one side of the engine it's either an intake manifold leak or a problem with the front O2 sensor. Here is some more info on the code for you.

P0171 FORD - Fuel Injection System Too Lean Bank 1
Read more: https://www.autocodes.com/p0171_ford.html