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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Mercedes
Satisfied Customers: 2350
Experience:  Owner at Carolina Auto Service & Sales , 20 years experience in Foreign & Domestic vehicles
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I have a 1997 Mercedes S500 sedan with 58000 original miles.

Customer Question

I have a 1997 Mercedes S500 sedan with 58000 original miles. It stalls when idling sporadically,but the frequency of the stalling incidents is increasing.It runs normally on the highway, but the engine shuts off when I stop at a traffic light. The engine all so shuts off when idling while setting still in Drive or Neutral Sometimes it will almost shut off and then suddenly surge back to higher than normal idle RPM, and then settle back to the normal idle RPM
Submitted: 9 months ago.
Category: Mercedes
Expert:  Chad Farhat replied 9 months ago.

Hi my name is***** will try to assist you .

the surging problem and stalling at idle is usually a bad mass air flow sensor on these cars , if there is no vacuum leaks

1-has the mass air flow sensor ever been changed ?

2- they can be bad WITHOUT setting any mass air flow codes in the computer .

let me know so i can go further with it , thanks

i will be online most of the day today

Customer: replied 9 months ago.
The mass air flow sensor has not been changed during the 4 years I have owned the car.. Where is it located on the car, and is it difficult or require special tools or precautions to remove and replace?
Expert:  Chad Farhat replied 9 months ago.

no you can do it yourself , I will send you the part # ***** picture if you stay with me few minutes

Expert:  Chad Farhat replied 9 months ago.

there is also other things we need to check but we will get to that , do you have a code reader for it that can retrieve ecu codes ?

Expert:  Chad Farhat replied 9 months ago.

Manufacturer Part Number:

128 33004 102

you can buy them for $60 but you want the OEM BOSH ONE and they are around $250,Trust me On this one :)

Expert:  Chad Farhat replied 9 months ago.

# ***** in that diagram is the mass air flow sensor

Expert:  Chad Farhat replied 9 months ago.

hey you still with me

Expert:  Chad Farhat replied 9 months ago.

we also need to check that the mass air flow sensor electrical connector is making good contact and not melted , burned or cracked causing you the intermittent signal back to the ecu .

Expert:  Chad Farhat replied 9 months ago.

I will be online most of the day .Thanks