Repair Safety Notice:
This information is for general instructional purposes only. Vehicle repair can be dangerous.
Verify all information, follow manufacturer service procedures, use proper tools and safety equipment,
and consult a qualified repair shop when needed.
BMRFIXIT
AUTOMOTIVE REPAIR CONTRIBUTOR
19,053 POSTS
The codes P0171 and P0174 both indicate that the engine's air-fuel mixture is running too lean. Here is a guide to help you fix it but I can tell you a clogged fuel filter, vacuum leak or a bad MAF sensor can cause this problem.