Engine light and shaky idle.
jw
Your symptoms are similar to mass air flow sensor i had on my s500, a cheap fix.
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Basically the spark plugs and one of the coils were at issue, causing the car to run on half the cylinders.
On the 600, of course, that was over $3k to replace the coil and spark plugs




The coil pack was paid for my MB, even though the car went of out warranty before.
For anyone that doesn't have a warranty on their MB:
It's important to know that if a car is less than 7 years old and has less than 100k miles, Mercedes will pay for the parts and even part of the labor as a courtesy if the Service Manager of the dealer asks for it.
Obviously it doesn't hurt to be a repeat customer and/or have a good relationship with your dealers service manager.
UPDATE: being told it is the number 1 coil causing a misfire, also the excess vibration is from a collapsed motor mount that I wouldn't have really noticed without this coil issue.
So how much to replace thus one coil? I'm on stand by to see if my warranty will cover it.
Last edited by Zerocarpileup; Nov 7, 2012 at 05:50 PM.
Do a quick google search on "S550 Ignition Coil" they're like $50 ebay has them also.
Motor mounts on autohausaz.com is $89.25 each for Sachs/Boge brand part number 2202403317(OEM according to them). Your car needs 2. If you are handy with tools, you can do them yourself in about 2-3 hours. An independent shop should charge around $200-300 to put them in if you provide your own parts.




The 600 has a just two coil units at $1500 each and have to be replaced as a whole. Lucky you...
If an individual coil is all you need to do, this sounds both easy and cheap to do, provided you know which cylinder is the culprit. EDIT Didn't see the comment about coil 1...
Personally, at 90K it may be time to change the set of plugs.
Re. the motor mounts, definitely do that, it will make your car run better and much smoother. This is something you shouldn't attempt unless you know what you are doing and have the tools. It's pretty cheap too.
On the 600, replacing the mounts alone is another $3k as they have to pull engine out completely. 18 hours labor!

Why is the warranty actually not covering the coil or motor mounts? That doesn't make any sense.
Last edited by Wolfman; Nov 8, 2012 at 05:29 AM.
2007 S550 RWD was driving on the highway fairly hard in sport mode on a nice day. Came off the highway after 20 mins of driving and straight to the gas station. I was pretty empty on gas on top of it. Filled up with 91 octane and hit the push start. Car started and then just died. Tried this 4-5 times and same thing. Then started and hit the gas and it would stay on as long as I held it above 1500 but sputter up to 3200 rpm. Got it towed home and searched these forums. There is another one titled Idle Problems for the same car. Anyhow I was inclined to check the MAF sensor along with other things after doing some research. As soon as I disconnected the MAF sensor and started the car the car was perfect running fine and idling with the only issue being the engine light on.
Next day ordered MAf sensor.. changed it and Voila! Car is perfect now.. Engine light came off.
Hope this info helps someone out. Total cost $ 200 cad and easy to change









