I have an 05 with 29K miles, automatic tranny, no mods.

It just started doing today, deaccelarate to stop sign- and the car almost cut off, I nursed the gas pedal it came back to normal RPM's- it happened three times today, first time ever happened. No check engine lights.

Twice when I accelarated the power didn't seem smooth.

Thanks for any suggestions.

Don

 

Did you recently fill up at a gas station? If so, you may have got a bad tank of gas either with water in it or debris that has plugged up the fuel filter.

 

Could be a vacuum leak, easy to check by getting a simple gauge and some hose to reach the engine thru the window. Get a youngster to listen to the idle and see if they hear a vacuum leak is an alternate, they still have the high freq hearing that fades with cars and age..........Woody

 

Gas purchased from the same BP station as always- they check their tanks weekly for water- tanks installed 5 yrs ago.

Thanks for your suggestion, I would change out the fuel filter as a last resort- but I don't think it is the culprit.

 

Checked no vacuum leak.

Thanks for your suggestion.

I still am having the problem- drove yesterday about 10 miles, slight hesitation after warming up, the car's RPM's did not crash down like it did when I drove it over 100 miles on Monday.

 

Pull the negative battery cable for 1/2 hour and then reattach. You're basically resetting the learned history in the PCM.

I had the same problem once at about 50xxx miles only when I exited the expressway......it hasn't come back.

 

I recently reset it inside the car.............

but

I just pulled the neg cable and cleaned the positive cable/post- had a little build up not much IMHO.

I will try to see if doing the negative cable helps.

Thanks for your suggestion.

Don

 

with 30K miles, you should have changed the fuel filter once already...

 

Pulling the battery cable for 1/2 hour will reset the PCM (powertrain control module)....... you usually reset the FSS (flexible service schedule) from inside the car.

 

Unless he is talking about resetting the PCM with the key+gas pedal trick from inside the car

 

That is what I was talking about.

Don

 

I would say its time to change fuel filter too !!!! 05 with 29,000 !!! Why not ?????

 

This would be the quickest fuel filter change in over 30 cars I have owned- I know where I buy my gas- where are you getting it is time to change the fuel filter? It may be the problem, I don't know- but with less than 30K miles and knowing where I purchase the gas from,,,,,

Thanks for your help and I know you are only trying to advise the correct things to do.

Don

 

That works excellent for resetting the drive-by-wire / throttle. It does absolutely nothing for resetting the PCM though.

 

Thanks for clearing that up for me Apkano- I didn't know there was a difference-

does taking off the negative cable also reset the drive by wire throttle and the PCM?


Thanks
Don

 

You also buy highly-regarded Mobil1 oil, but still change it and your oil filter every 7,500 miles right?

 

Yes- on the oil and oil filter.

 

Apkano-after resetting the PCM, I was so happy............ drove for about 15 miles had my old Xfire back-

however getting near my home, the stutter happened again, not as bad as before but still very evident to me, I was bummed again.

Thanks for your suggestion and I was hoping to offer a dinner on me, for the suggestion. Any other ideas besides the fuel filter, which may be my next try?

Don

 

Does the car still have the original OEM battery? If so, it is 6 years old, and there have been cases of older batteries with lower voltage causing weird symptoms in the Mercedes electronic systems.

I realize this is thin and is just a WAG on my part, but if you are soon due for a new battery anyway it may be worth a try. I'll be replacing my OEM battery next week even though I'm currently having no problems.

 

Battery has not been replaced but had my mech check it out- tested fine- do you think it could cause a problem when it tests OK?

Thanks
Don