How do i fix problem

Question

I changed out new spark plugs didn't fix it

Answer 1

Hi there

This code is for a lean fuel mixture on bank 1 of the engine. This is normally caused by a bad front O2 sensor when it's on a single bank, but it could also be the result of an intake manifold vacuum leak or exhaust leak as well. Here's some more info on it for you

P0171 FORD - Fuel Injection System Too Lean Bank 1

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