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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54036
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I have a 500E. When I step on the accelerator it stalls but

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I have a 500E. When I step on the accelerator it stalls but its ok when I accelerate very gradually. Check engine light is on
JA: Does the light stay on, or does it blink?
Customer: stays on
JA: What year is your 500e?
Customer: 2005 it has 225,000 mile
JA: Are you fixing your 500e yourself? What have you tried so far?
Customer: nothing...I just drove it 25 miles to work...its ok as long as I don't try to accelerate too has been below zero here two mornings in a row...could fuel be bad or have some condensation
JA: Anything else you want the mechanic to know before I connect you?
Customer: I di hit a pot hole pretty hard a week ago ...

Hi, welcome to Just Answer. My name is Marty.

What you are describing is a loss of fuel pressure or a problem with the fuel mixture. I'm sure that the fault codes that are causing the check engine light to be on are related to the mixture. If the fuel pump is failing or if one of the sensors for the mixture control are failing it will give you this symptom. The cold weather can make the problem worse. You will need to get the car connected to a Mercedes tester to read out the fault codes that are stored in the engine control module. The fault codes will point to the problem area. A fuel pressure test may also need to be performed. Another possibility is an air leak at the air intake. The intake system should also be checked for vacuum leakage.

Let me know if you have any questions. Please remember to rate my service :-)

And yes, a bad tank of fuel could be the cause but I would normally expect worse symptoms if you have bad fuel.

Please let me know if you need further assistance. Kindly rate my service when you are done.


Customer: replied 9 months ago.
I used some fuel injector cleaner with a new tank of gas and that cured the problem for now.

Excellent! Glad to hear it's doing better. Let me know if you need anything else. If you would please take a moment to rate my service I would appreciate it.

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