2001 Ford Windstar check engine code PO171 / PO174

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Computer problem
2001 Ford Windstar 6 cyl Front Wheel Drive Automatic 116, 00 miles

I have had the reocurring check engine light from hell.I have changed sensors, filters and taken the injectors out and had them professionally cleaned and still the check engine light comes on. I hear no sound of a vaccum leak. Do you guys have any other ideas?

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Wednesday, June 25th, 2008 AT 4:02 PM

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2001 Ford Windstar check engine code PO171 / PO174

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)

* TIP: On many Fords, a P0171 and/or P0174 Lean Code may sometimes appear because of a bad Differential Pressure Sensor (DPFE). This sensor monitors EGR flow, and is located on the engine near the EGR valve. There are two hoses that connect the sensor to the tube that runs from the exhaust manifold to the EGR valve. The sensor misreads EGR flow and the computer increases EGR which has a leaning effect on the fuel mixture. The fix is to replace the DPFE sensor.

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Wednesday, June 25th, 2008 AT 4:19 PM

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