It just started this morning. I started the engine and it was vibrating or shaking wildly at idle. Once I drove the car and it was warmed up it went away. It hasn't happened again yet today will see tomorrow morning. Any suggestions? The car is up to date with maintenance items: plugs, fuel filter, etc..

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Joe95E420

I'm not sure of the failure mode for engine mounts, but it's worth a check. I know the MB engineers designed cooling ducts from the front of the car specifically to bring cool air to the mounts during driving (tke a look in your car - it's very strange). I guess that the heat of the M119 engine can deteriorate these mounts.

Does it seem like your car is missing or knocking? Or is it just a general roughness?

Mileage of the car would help diagnosis too.

Good Luck,
Troy 1995 E420

How do the distributor caps look? They can sometimes be an issue on cold start, especially if they are not Bosch.

Knowing me, I couldn’t just sit and wait on such a problem. I decided to take advantage of my MB service department was able to look at the car soon yesterday so took in my car. I had planned to take in the car anyway after i found some oil leaks a couple of weeks ago coming from the front lower engine side.. the oil leak looked like it was coming from the oil filter housing, but like with any oil leak it is hard to tell the source after the car had been driven and the oil trace is lost. Oil was dripping from all around the lower oil pan and the upper oil filter housing etc..
So once at the dealer, I told the service advisor about the vibration issue and also asked them to take a look at the leak situation while they are at it... a couple of hours later the service advisor came back and told me they could not duplicate the vibration mainly because the car is not cold anymore... as for the oil leak they have found that the upper valve cover gaskets leaking... they also said their is suspicions that the oil filter housing and the lower oil pan gasket are leaking, but they weren't sure. I changed the lower oil pan few months ago and the gasket was new so i didn't think that was a problem. So thinking logically, I thought it would make sense to start fixing the leak from the top first without having to spend too much $$ and asked the dealer to replace the valve cover gaskets (both R/L) and leave it at that (~$400 job). While they were doing so they also discovered a small vacuum hose with some cracks and they replaced that ($11 no labor!) and picked up the car… so far no hesitation or vibration… I crossed my fingers this morning when I started the car… NO vibration…. So was the vibration caused by the small crack on the hose? Or was it related to a leaky valve cover gasket? Whatever the answer maybe… hopefully that fixed both issues for me: the leak and vibration. Car drives like a champ once again. I’ll let you know if it happens again.

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Joe95E420

The vibration was caused by the leak in the vacum hose.... a minor oil leak in the upper valve cover gaskets would not cause a vibration in the engine.

When is last time you changed the oxygen sensor? I have same model and year. It terribly shakes and vibrates during cold and hard running. I am looking to replace oxygen sensor. Mine has 112K miles on it. It had been running rough for quite a while now.

Thanks

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Kamal Atwal
2005 Triumph Bonneville T100 (Black/white) [Sold]
2007 GL450 (Dersert Silver)
2009 Toyota Corolla (Metallic Silver)
2002 Tundra V8 - 2WD (Desert Sand)
1995 MB E420 (Silver Smoke) [crashed, now resting in peace at Silverstar Recycling Center]

since the car has only 41k miles. Didn't think it needs it.. yet!

rsmcmahon,
I think so too, but why would the vibration occur during cold start only? Just curious...

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Joe95E420