Vrodman

He Guys,

I mentioned this issue in another thread but wanted to give it its own thread. Here's the specifics:

Just bought the car 2 weeks ago with 31,000 miles on it.

It has 6 weeks left of factory warranty.

Car had all of its services performed by dealer as scheduled before me.

I have an appointment for Wed to have this idle checked out.

I just know from previous experience with the Benz Dealer that if the problem is not obvious, it doesn't get solved or it get flat ignored.

I am hoping for some true gear heads out there that may know exactly what may be to blame for the issue so I can request certain diagnostics from them.

Example: bad ignition coil, ignition wire, etc. Something I can make sure they check out. OBD did not reveal any trouble codes to give clues. I really just don't want to get shined on until it's out of it's 4 year warranty and into its aftermarket warranty.

It does not seem to be motor mounts. Tried it in drive, N, and Park and vibration does not change. If it were motor mount it usually gets much better when put in N or Park.

I am thinking it is some type of misfire. I did notice that the vibration seems strongest after downshifting and using engine/trans to come to a stop. Almost as if something gets out of whack from the trans breaking. But it still does exhibit off and on even when not stopping via downshifting.

Could this have to do with the wet clutch and not be engine at all? Probably not if it does it in Park and Neutral right?

Any ideas?

AMGJAY

Can you post a video? Mine as well has a rough idle. Sometimes it feels like it's punching. For example. If you have your foot on the brake, you can feel the hits. Almost like a heartbeat. A bit strange but I haven't bothered to really check it out as I have the extended warranty through MB. Something I'd definitely get checked out before warranty is out though.

Vrodman

I could post a video, but honestly it wouldnt show much. The problem is not terrible and really shaking. It just isnt Benz quality. Best indicator is when I look at a bottle of water in the cup holder and I can see ripples at the top.

Wife feels it. And she has a 2014 GLK350 to compare against.

My private mechanic immediately felt it when I had him inspect the car before I bought it. He still recommended I buy the car based on the deal I was getting and that I could still take it to the dealer to get the idle fixed. He wasnt sure exactly what it might be as no OBD trouble codes came up related to idle. He did think that the dealer guys, with more time, would figure it out though.

Even my 16 year old (yes, I bought that one new) E55 never had idle vibration until she needed a motor mount.

Celicasaur

Mine has a minimal idle wobble too. I just thought it was a characteristic of the v8. seems to jump around by 50rpm or so when idling.

Vrodman

Dropped the car off at dealer this morning and they had a foreman mechanic/tech take a drive with me. The tech did feel the idle issue and did confirm that it is not right.

His initial thoughts are that it is not serious and likely only a vacuum leak. He did say they would get it fixed though one way or another.

I will update after I get the car back. Hopefully I will get it before the weekend.

Vrodman

So after the mechanic told me yesterday that the idle did not feel right, I get a status update call today and my adviser tells me that the techs checked it out and couldn't find any manifold leaks or other vacuum leaks of any kind, and he went on to say that they actually thought the idle was fairly normal.

So now that they can't find an easy solution, it is normal? Huh?

So to quantify what I am feeling with the idle, it is not horrible. It is not as bad as when one of my E55 motor mounts went bad for example. It does not fell like a 70's muscle car with a radical cam!

It is simply noticeable. Best way to describe it is imagine you have a bottle of water in the cup holder and while in idle the water at the top is getting small waves.

Does this sound normal? Anybody ever see "rough water" in their cup holder while sitting in P, N, or D?

Maybe I'm nitpicking ?? Maybe a 6.2 litre 518 Hp engine will have a minor wobble?

screw991le

Your driving a 500+ HP beast. The idle on a supercar is going to be erratic at best. You did not buy a purring E350 you bought a hell bound beast. IMHO.

Mine has been rippling for years, and I love it.

PeterUbers

Uuuhhh.... My water is flat at idle .... Smooth as can be

Davidkuo0330

Sorry for the late responds. My AMG doesn't have this problem, but it's funny you asked because my 2011 E350 does that. I especially can feel it when I'm getting on the freeway with the E350 and am trying to give it gas and then when you brake and the car actually feels it jerks forward.

I went to 3 different MB dealers and one shop foreman went on the test drive with me and felt it too, but when they did their diagnostic check. Dealer says its within Mercedes guildline however I feel something is wrong.

Service department tells me a story that the Mercedes learns your driving pattern and when you drive out of place, the car thinks you want to give more gas so the car jerks when you break. I know it's a messed up excuse, but been to 3 dealers and all tells me the E350 is fine.

I hope I'm on the same page as to your inconsistent idling inconsistent idling issue.

Please keep up updated the outcome. Thanks.

Vrodman

UPDATE

My engine idle issue that was consistantly on and off for the first few weeks of owning her as pleasantly dissapeared!!

Haven't felt in a few weeks now. I am guessing that my harder driving style, than perhaps the previous owner, broke some piece of crud loose that was causing it. Like sparkplug gunk or something.

Now I couldnt be happier with my girl! Love this car!

Just thought I would share.