Rough idle on "Cold" start
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 15
Likes: 0
From: NJ
11 E350 4Matic
Rough idle on "Cold" start
First I just want to start of by saying this site has been a great resource to me and thank everyone who post as it really helps diagnose possible problems before they arise so a big thanks to everyone for that.
Vehicle: 2006 E350 4Matic 65k miles (Oil just changed at 64k)
The past two morning I have been in a rush and have noticed that when starting the car and just just driving off after about a minute or so of "warm up" when I stop at say a traffic light and the car sits for like 2 to 3 minutes the idle gets shaky (almost along the lines of a misfire shake), once I begin to accelerate the car will make a rough change into the next gear. Now I normally let the car heat up as I live in New Jersey and the past few morning have been 25 to 28 degrees, so my question is should I chalk this up as cold start, car needs to warm up, as after it does get warm its smooth sailing again. Or could this be a sign of something going wrong, as I am not seeing any check engine lights or anything but am concerned and would rather head this off than wait for it to be a full blown problem. Any help you guys can provide would be greatly appreciated. Thanks in advance.
Vehicle: 2006 E350 4Matic 65k miles (Oil just changed at 64k)
The past two morning I have been in a rush and have noticed that when starting the car and just just driving off after about a minute or so of "warm up" when I stop at say a traffic light and the car sits for like 2 to 3 minutes the idle gets shaky (almost along the lines of a misfire shake), once I begin to accelerate the car will make a rough change into the next gear. Now I normally let the car heat up as I live in New Jersey and the past few morning have been 25 to 28 degrees, so my question is should I chalk this up as cold start, car needs to warm up, as after it does get warm its smooth sailing again. Or could this be a sign of something going wrong, as I am not seeing any check engine lights or anything but am concerned and would rather head this off than wait for it to be a full blown problem. Any help you guys can provide would be greatly appreciated. Thanks in advance.
Senior Member
Joined: Jul 2007
Posts: 421
Likes: 14
From: Bay Area
2004 E500 CLK320
My guess is that the idle control valve and the throttle body need cleaning. The throttle may not open all the way (or sticky) at cold. Rough idle at cold is a common problem to many old or high mileage cars.
Last edited by SZMB; Jan 15, 2010 at 05:08 PM.
Member
Joined: Aug 2009
Posts: 107
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E500
Senior Member
Joined: Jul 2007
Posts: 421
Likes: 14
From: Bay Area
2004 E500 CLK320
Not that easy on the E or C class. The throttle body & ICV are mounted on the back of the engine, after the mass air sensor. There's not much room to work with. I haven't done this on the E class, but did it on the 1999 C280. It took me about 2 hrs to remove the throttle body and then cleaned it with carbureator cleaner. I couldn't find a good angle where you can just spray the carbureator to the throttle body and ICV, that's why I had to removed them to get a good cleaning.
However, this job is super easy on the BMW 3 or 5 series, where the throttle body and ICV are mounted on the side and you don't have to remove them from the engine. It's a 30min job on the bimmer.
However, this job is super easy on the BMW 3 or 5 series, where the throttle body and ICV are mounted on the side and you don't have to remove them from the engine. It's a 30min job on the bimmer.
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 15
Likes: 0
From: NJ
11 E350 4Matic
SZMB, I had the throttle body thoroughly cleaned and I could immediately tell the difference when I turned the key. The car started up very smoothly, and gear changes have been just as smooth. The true test will be on a cold start again, but so far this seems to have done the trick.
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