engine shaking @ cold start...
MBWorld Fanatic!
Joined: Aug 2007
Posts: 1,544
Likes: 87
From: San Jose, CA
2010 c300
I bought mine used last year and it's always done this in a cold start. But its very mild. Feels like the engine is misfiring a bit. Then about 20 seconds later I hear a 3 second whining sound from the engine. When that stops the engine no longer shakes. I've just assumed this was normal as the car was warming up.
Newbie
Joined: Jun 2014
Posts: 3
Likes: 0
C280 2008
I think its kind of quick misfire! and it depends what type of fuel you are using the new mb engines are very sensitive for the carbon level .. i had the the same story plus check engine light on and off .. try to use high octane fuel and you'll notice the different from the next morning 
Super Member
Joined: Dec 2013
Posts: 879
Likes: 10
From: Tampa, Florida
2011 C300 4Matic Sport
I think its kind of quick misfire! and it depends what type of fuel you are using the new mb engines are very sensitive for the carbon level .. i had the the same story plus check engine light on and off .. try to use high octane fuel and you'll notice the different from the next morning
California has 91 octane as highest.
And still hear it
In my opinion, since the catalytic converters are not warmed up yet, you will hear a misfire such sound.
That is why, on any car, the odor of gas is present on a cold start.
This could be related also; condensation in the exhaust from humid climates.
If the "misfire" happens in dryer climates, then I would guess I am wrong about it being condensation.
