Island_Moose

Occasionally when I'm stopped at a traffic light the normally smooth idle will tremble for a second or two and then come right again. You can just see it happening on the tach needle, but you can feel it (that anxiety you get when you think it's just run out of fuel). Started after I took it to the dealer for new plugs, oil and transmission flush.

Runs perfectly in every other way. I've scoured the forum and I see reference to intake leaks, but it's so intermittent it feels more electrical. Any thoughts? I can obviously call the dealer and ask, but you all might save me some time and money.

hachiroku

my car would do that maybe........once every 2 weeks. can't recall the last time it did it since i had my full service completed. could be something as simple as fuel trims making adjustments. i'd check for leaks around your intake boxes or tubes, but without proper monitoring or scanning it could be anything.

oneslow55

Dirty injectors ,or bad plugs can cause this ..Get a fuel cleaner run the car wot and see of it clear's.

This care need to be run wot least 1 time every 2 weeks or you can cause carbon build up causing stumble issues as stated!

Island_Moose

It wouldn't surprise me if this is the problem, she very rarely gets driven hard.

hachiroku

that's like having a hot wife and never letting her out of the house. you show pictures of her but she doesn't exist in person.

live your life man.

MACEDON

Redline fuel system cleaner tbh, buy a 3 pack and run em back to back

or Gumout one n done

or BG fuel system cleaner

Point is your ****'s clogged up. I gave run a plethora of fuel system cleaners in the past year of ownership starting with Techron, honestly the car runs smooth as butter straight up because of them.

I'm sure that replacing the injectors or having them cleaned (if such procedure exists) woul've produced similar results. Driving the car hard is nice but I'd say add some chemical to your fuel to help it.

PieRat

Yeah my idles **** too. Annoyingly it goes away when hot(or virtually does), can't be o2, map, iat senssor.. What is most likely? Plugs have onky done 25,000km..I have tried fuel cleaner treatment and I WOT every day or time i drive it...

MACEDON

Vacuum leak?

FunkTron

my local dealer senior technician said explicitly that it is the fuel map.
he said it goes lean for a second then comes correct again. His exact quote was "it's not fixable"

PJmak

Get a new senior technician

PJmak

I was told by experienced mercedes techs not to run any of those things through your car. How sure are you that he should run that and can you guarantee that itll work and not mess anything up?

oneslow55

Yep ..lol..

That was the dumbest thing I ever heard..

Now ,if you had headers and got that stumble then it's due to the car breathing harder.

I Can bet you it's the car clogged up and needs to be cleaned up.

MACEDON

You can change out the sensor it's just a pain without removing the SC