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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53016
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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Stalling out. Just had air pump replaced. I think it maybe

Customer Question

Stalling out. Just had air pump replaced. I think it maybe o2 sensors. The gas level sensor is broken and check engine light is on. Ml
JA: It's good that it's giving you information about the problem. The Mercedes Mechanic will know what to do. Tell me a bit more about what's going on so he can help you best.
Customer: The car hesitates when I accelerate and cuts off at times when going down an incline such as a driveway and has sluggish pickup. Ml 320
JA: Are you hoping to fix this yourself?
Customer: No
JA: OK! The Mercedes Mechanic will help you with the diagnostics so you are sure to get this fixed right. Is there anything else the Mercedes Mechanic should be aware of about your Mercedes?
Customer: Chef
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and then connect you two.
Submitted: 5 months ago.
Category: Mercedes
Expert:  Marty replied 5 months ago.
Hi, welcome to Just Answer. My name is***** faulty oxygen sensor can cause poor running but it is not a very common symptom of a bad sensor. The first step in diagnosing this problem is to get the car connected to a Mercedes scan tool that can read out the fault codes in the engine control module. The fault codes will more than likely point to the cause of the stalling. A more common cause of the symptom that you describe would be a fault with the mass air flow sensor. The sensor is most responsible for the fuel mixture for the motor. It sounds like the car may be getting too little fuel. This is why it hesitates and stalls. Vacuum leaks at the intake can also cause this problem. Another possible problem would be a fault with the fuel pump. A weak fuel pump could also give you these symptoms. I'd suggest getting the computer scanned for fault codes and checking the intake system for vacuum leaks and checking the fuel pump pressure. A new mass air flow sensor can easily be substituted for testing purposes.Let me know if you have any questions. Please remember to rate my service as this is the only way that I can receive credit from the website for helping you.Marty