p0171 p0174 adaptive fuel running too lean
Sep 25, 2009 at 2:48 PM
2002 Ford F250 smog codes
2002 FORD F-250
PACIFICSURFER195125
- MEMBER
- 1 POST
- FOLLOW
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.
Advertisement
P0171/P0174
A lean fuel condition can be caused by:
* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)
* Dirty fuel injectors. (try cleaning the injectors)
* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)
* Leaky EGR valve. (Check operation of EGR valve)
* Leaky PCV Valve or hose. (Check valve and hose connections)
* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)
A lean fuel condition can be caused by:
* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)
* Dirty fuel injectors. (try cleaning the injectors)
* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)
* Leaky EGR valve. (Check operation of EGR valve)
* Leaky PCV Valve or hose. (Check valve and hose connections)
* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)
Sep 25, 2009 at 2:50 PM
Advertisement