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What year is your Windstar and which engine do you have? How is your van running? Is this the only code?
The lean codes is almost always caused by unmetered air. On your van it's usually the valve cover, fuel regulator hose, intake seals and port bolts as well as a PCM reflash. Ok I think we should start by clearing the keep alive memory which you may be able to do with your scan tool or you can just disconnect the battery. Also let me know the year and if you have the 3.8 liter. Next start the engine while monitoring the fuel trims and oxygen sensors. Try spraying some carb cleaner around the intake looking to see if the trims lower or go into the negative. You can also try to smoke leak test the intake. Here is the test we use.
MALFUNCTION INDICATOR LAMP (MIL)ILLUMINATED - SYSTEM LEAN DIAGNOSTICTROUBLE CODES (DTC'S) - SERVICE TIPS
FORD:2000 Contour2000-2002 Escort2000-2003 Escort ZX22000-2004 Crown Victoria, Focus, Mustang, Taurus2002-2004 Thunderbird2000-2003 Windstar2000-2004 Econoline, Excursion, Expedition, Explorer, F-Super Duty, Ranger2001-2004 Escape2004 Freestar2000-2004 F-Series
LINCOLN:2000-2002 Continental2000-2004 LS, Town Car, Navigator2002-2003 Blackwood2003-2004 Aviator
MERCURY:2000 Mystique2000-2002 Cougar2000-2004 Grand Marquis, Sable, Mountaineer2004 Monterey
This article is intended to aid in diagnosing DTC's P0171, P0174, P1130, P1131, P1150, P1151, P2195, or P2197 (system lean or lack of HEGO switches) when a vacuum leak is present. HEGO sensors, MAF sensors, and PCM replacements are not an effective repair when a vacuum leak is causing the above DTC's.
Perform the following inspections/repairs when the above codes are found in memory. Procedure provides instructions on how to make comparisons of the total fuel corrections (using scan tool or equivalent) at idle and high RPM's to help determine if a vacuum leak is the root cause of the DTC's.
NOTE FREEZE FRAME AND ADAPTIVE FUEL VALUES (ASSOCIATED WITH "LONGFT" PID) WILL NOT BE AVAILABLE IF A KAM OR OBDII RESET WAS RECENTLY PERFORMED.
NOTE FREEZE FRAME DATA WILL INDICATE THE ENGINE AND AMBIENT CONDITIONS WHEN THE DTC WAS SET. THESE ARE IMPORTANT BECAUSE THE VACUUM LEAKS MAY OCCUR ONLY WITHIN SPECIFIC TEMPERATURE RANGES AND MUST BE DUPLICATED TO DETECT THE LEAK.
NOTE FUEL TRIMS AT IDLE ARE PARTICULARLY SENSITIVE TO VACUUM LEAKS SINCE THE UN-METERED AIR "LEAKAGE FLOW" IS A HIGHER PERCENTAGE OF TOTAL AIRFLOW AT IDLE THAN AT PART THROTTLE. THE BAROMETRIC PRESSURE (BP) PID IS NOT RECOMMENDED TO VIEW WHEN DIAGNOSING A VACUUM LEAK. BP IS AN INFERRED PID CALCULATED DURING HIGHER ENGINE LOADS.
A TYPICAL VACUUM LEAK WHICH MAY SET A LEAN CODE DTC WILL HAVE TOTAL CORRECTION OF AROUND +20% OR GREATER AT OR NEAR IDLE (DEPENDS ON CALIBRATION)