Mechanics

TROUBLE CODE P0171 AND P0174 WITH EVAP.

2002 Ford Explorer

Engine Performance problem
2002 Ford Explorer 6 cyl Four Wheel Drive Automatic 106000 miles

p0171and p0174 codes on truck, already have replaced egr valve and sensor and dpfe. Thinking maybe o2 sensors or airflow sensor? Any help would be great. Mileage has gone way down. Thanks.
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32john32
January 11, 2010.




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)

Rasmataz
Jan 11, 2010.


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