Car shakes in cold engine
Whenever the car starts in the morning (in cold engine), after about 5 sec, car shakes a lot for 3-5 sec. It's very noticeable, but the dealer kept saying it's normal that the car shakes in a cold engine.
I really don't think this is a normal.
Any idea what is causing it?
Perhaps, the previous owner used non-premium gas???
HELP! Please!!! I am getting frustrated
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Also, this is another issue we found. It doesn't happen all the time, but some times when he goes above 75mph or higher and let goes the gas pedal, speed decreases rapidly. Any idea why?
Thanks!!
As far as the "rapid" decrease in speed, rapid is a subjective thing. Hard for us to say... Perhaps the engine downshifts as you let off the throttle (which slows the car down more) as the car predicts you're wanting to stop or slow down. It could also just be that the car you previously had "coasted" much easier?
As far as the "rapid" decrease in speed, rapid is a subjective thing. Hard for us to say... Perhaps the engine downshifts as you let off the throttle (which slows the car down more) as the car predicts you're wanting to stop or slow down. It could also just be that the car you previously had "coasted" much easier?
Thanks for the reply.
Two things. The shakiness is not just a small shake. The whole car shakes. Compare to the loaner car it's about 3times. Is it still normal for mercedes?
Also, the speed decrease issue.... it's the point where I almost had an accident.
Does anything has to do with using non-premium gas??
Thanks again!
Two things. The shakiness is not just a small shake. The whole car shakes. Compare to the loaner car it's about 3times. Is it still normal for mercedes?
Also, the speed decrease issue.... it's the point where I almost had an accident.
Does anything has to do with using non-premium gas??
Thanks again!
As far as your deceleration issue... have you mentioned this to the dealer?
Also, was your car a CPO (Certified Pre Owned)? Did you buy it from a MB dealer?
As far as your deceleration issue... have you mentioned this to the dealer?
Also, was your car a CPO (Certified Pre Owned)? Did you buy it from a MB dealer?
I don't know what else to do. I use premium gas only but I can't do anything if the previous owner used non-premium gas before.
I am considering to see the lawyer if they can't fix this issues.
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As far as the "rapid" decrease in speed, rapid is a subjective thing. Hard for us to say... Perhaps the engine downshifts as you let off the throttle (which slows the car down more) as the car predicts you're wanting to stop or slow down. It could also just be that the car you previously had "coasted" much easier?
You need to delete your entire post since it is technically a fantasy.
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I don't know what else to do. I use premium gas only but I can't do anything if the previous owner used non-premium gas before.
I am considering to see the lawyer if they can't fix this issues.
I might be going out on a limb here... but your "deceleration" issue doesn't happen ALL the time, right? I can honestly say that the car's blinker takes some getting used to because the cruise is set right there above it (where most cars have their blinker). Do you think he may have hit the cruise to set at a certain speed (thinking he was hitting the blinker), then sped up the car? When he releases the gas it will try and go back to what the car's cruise speed was set to, and it will hit the brakes in order to do so (rapid deceleration).
I'm still uncertain about your shakiness on cold starts. But it is still under warranty and may be worth pursuing legal action if they continue to ignore the problem and say they could not replicate it.
Last edited by aMsupp; Oct 17, 2012 at 11:03 AM.
I'm still uncertain about your shakiness on cold starts. But it is still under warranty and may be worth pursuing legal action if they continue to ignore the problem and say they could not replicate it.
Yeah, I think I will see the lawyer soon if they can't fix the shakiness.

The M272 engine should not shake excessively on cold start, high idle, full open loop enriched running. Some of this can depend on just how cold it is & fuel used. i.e summer or winter grade.
However, the M272 uses very soft silicone fluid filled mounts. Some shake is inevitable until stable idle but you should not feel it inside the car.
Don't touch the throttle at cold start. Just crank the car.




