po171 2002 kia sportage

Question

I have replaced both, 02 sensor up stream and down stream and yet the po171 still comes up and very bad gas mileage.  car picks up at a full stop very quick but if is should slow down and accelerate again it gets very sluggish

Answer 1

HI there,

The lean fuel mixture code could also be the result of low fuel pressure, a bad mass air flow sensor or intake manifold leak. All of these could cause the O2 sensor code to appear as well. Also, check the catalytic converter.