how to diagnois & repair p0171 on 2002 ford e-250 5.4l

Question

loss of power like on a hill or in passing & gas mileage then ck engine light came on

Answer 1

Hi there

There can be several causes for this code. Basically the code is saying the bank 1 fuel mixture is off and is to lean. Usually this could mean an intake manifold gasket leak on bank 1. However with the power issue going up hill it could also be low fuel pressure or a problem with the mass air flow sensor.