My 2009 ML63 has 120000km on it now and it was all fine until last weekend all of a sudden I felt vibration when I stop at a stoplight. I can feel the vibration sitting in the car and feel it from the steering wheel also. I check the car out and found I have low steering fluid so I fill it up and thought it would go away but it haven't. So I think if it would be the MAF sensor so I took them out and cleaned and reinstall everything including new air filters but no luck. I tried unplugged the MAF sensor and drive the car for a bit and still no luck so it seems not to be the MAF problem.

My question is that will it still be the steering pump problem even after I refill the fluid, but the pump has already gone wrong and creates vibration? The car only vibrates at idle though car steers fine and runs fine and performs fine when in motion.

One thing I also notice is that the secondary air pump that pumps air into the engine via 2 metal valves beside the steering wheel fluid reservoir, the air pump vibrates a lot when it operates and makes a loud noise too. I haven't really look at that pump before so I dont know if that is normal or if it actually caused the engine vibration.

As of now after a week of everyday driving the car does not have any CEL lights. Car only vibrates at idle but RPM didnt fluctuate or anything, it vibrates no matter if is in gear or not. All temps are very normal, I did kind of notice a deeper exhaust tone but maybe is just me thinking too much or too focus on it it could be like that before too.

One other thing I notice too is that if I put the car in reverse, it seems to vibrates more then if is in other forward gears or N or P. Car shifts very smooth with no problems at all at all rpm and speeds.

Does anyone have similar vibration happens to their car before and please help me with some ideas if you guys have any experiences! Thanks so much!

 

I also have a strange vibration at Idle.
Mine is a 2010 ML550 with 55K miles.
I start the truck in the morning after sitting all night, drive about 50 feet to the end of the driveway and wait for traffic. I am in Drive but stopped. The truck sometimes vibrates hard almost as if it is going to stall. It does this in waves. It happens for a few seconds then stops for a few, then happens again and so on. It shakes the truck hard enough for me to think its going to stall. I look down at the RPM's expecting them to be jumping up and down but they are always steady at about 800. They never change during the vibration/shaking.
This vibration seems to go away once the truck has warmed up and I never feel it again for the rest of the day. So far its happened on the cooler morning we've been having, below 60 degrees.
The spark plugs were replaced at 52K miles so I hope its not those.
Brought it to the dealership but of course they cannot duplicate the problem.
Any ideas?