Car Problem Reports

Mercedes-Benz S420 Faulty Mass Air Flow Sensor Causing Erratic Engine Operation and Poor Fuel Economy

 
Mercedes-Benz S420 Problem
14 Reports
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Model Years Affected: 1994, 1995, 1996, 1997, 1998, 1999

Average Mileage: 153,671 mi (109,000 mi - 303,498 mi)

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A faulty mass air flow (MAF) sensor can cause erratic/rough engine operation and fuel economy issues. Since this sensor measures the actual amount of air entering the motor, when it fails, the engine control module (ECM) takes the wrong information and delivers incorrect volumes of fuel to the cylinders.

  •  Enthusiast

    Was getting engine fault. Cleaned sensor located in driver side air intake using CRC MAF Sensor Cleaner purchased at Kragen (now O Reiley Auto Parts). Cleared fault using LED/ Pushbutton feature (may not be available on all models). Works perfectly.

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  •  Rookie

    I was told that My mass air flow unit is going bad. Is there any way to clean it or do I just have to replace it.

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  • Visitor, , 141,326 mi

    veh had starting running rough and losing gas mileage can smell the strong ordor of fuel with white smoke coming out

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  •  Rookie

    I HAVE THE SAME PROBLEM ITS LIKE THE COMPUTER HAS TO FIGURE OUT WHAT TO DO WHEN YOU HIT THE PEDAL AND ONCE IT RELISES WHAT TO DO IT GOES LIKE A ROCKET!

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  • Visitor, , 165,000 mi

    I have a similar problem, especially when the car sits for a while without driving. I always keep a can of MAS air spray in my car. By removing the cover over the MAS unit, I spray a small amount into the unit; it works like a charm.

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  • Visitor, , 303,498 mi

    Low MPG and terrible idle noises

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  •  Rookie

    runs poorly, with rough idle, has no power when driving. How often should I spray the sensor and or do I need to change wires?

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