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Questions and Answers

Ford Mass Air Flow Sensors

Q. I have a 1995 Ford Explorer 4x4, 89,000 miles, automatic transmission, 4.0 liter engine. When sitting still and idling, the engine rpms fluctuate between around 800 to 1000. Also, there seems to be some hesitation in acceleration until reaching highway speeds (55 mph - 65 mph). I have replaced the fuel filter, and spark plugs and still have this problem.

Ford Mass Air Flow Sensors

I have read that there is a problem with the Mass Air Flow sensor on these vehicles. If this is a possibility, where is it located and can it be cleaned?


A. Yes, there is a TSB on this.

Article No.: 98-23-10
Date: 11/23/98
Mass Air Flow (MAF) - Sensor Contamination

It is a rather lengthy document, a copy of which you may be able to get from your dealer, but after all is said and done, there is no procedure for cleaning the MAF, Ford says it has to be replaced.

And from the symptoms you describe, it sounds like it is the cause of your problem.

And just for informational purposes for those who are reading this. The affected vehicles are:

1990-97 Thunderbird
1990-99 Mustang, Taurus SHO
1991-99 Crown Victoria, Escort, Taurus
1992-94 Tempo
1993-97 Probe
1995-99 Contour

1990-97 Cougar
1991-99 Continental, Grand Marquis, Sable, Town Car, Tracer
1992-94 Topaz
1993-98 Mark VIII
1995-99 Mystique

Light Truck:
1990 Bronco II
1990-97 Aerostar
1990-99 Ranger
1991-99 Explorer
1994-96 Bronco
1994-97 F Super Duty, F-250 HD
1994-99 Econoline, F-150, F-250 LD, F-350
1995-99 Windstar
1997-99 Expedition, Mountaineer
1998-99 Navigator
1999 F-250 HD, Super Duty F Series

  • Lack of Power.
  • Spark Knock/Detonation.
  • Buck/Jerk.
  • Hesitation/Surge on Acceleration.
  • Malfunction Indicator Lamp (MIL) Illuminated. DTCs P0171, P0172, P0174, P0175 may be stored in memory.


  • P0171, P0174 (Fuel system lean, Bank 1 or 2)
  • P0172, P0175 (Fuel system rich, Bank 1 or 2)
  • P1130, P1131, P1132 (HO2S11 lack of switching, Bank 1)
  • P1150, P1151, P1152 (HO2S21 lack of switching, Bank 2)


  • 181, 189 (Fuel system lean, Bank 1 or 2)
  • 179, 188 (Fuel system rich, Bank 1 or 2)
  • 171, 172, 173 (HO2S11 lack of switching, Bank 1)
  • 175, 176, 177 (HO2S21 lack of switching, Bank 2)
  • 184, 185 (MAF higher/lower than expected)
  • 186, 187 (Injector pulse width higher/lower than expected)

Ford Mass Air Flow Sensors

Additional Information provided courtesy of ALLDATA

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