Here we go.
Start the engin, let in settle down after fast start idle, then advance rpm to 1100--1200.
At that rpm I get a "rolling" sort of rumbling vibration. Sort of the same one would get with a worn universal joint at slow speeds.

Check the engine visually and it is as smooth as if not running, but hold your hands on the engine and you can feel the same thing. Sort of like "rum-rum-rum-rum" . (Explaining this is hard) Maybe two "rums" each second.

No warning lights or codes indicating an induction leak of Vac leak. Maybe an injector acting up or fuel meatering system? who knows.

Driving down the road at normal speeds, gues where the RPM is. Correct. At 11-1200 RPM.

Any idea's appreciated.

Chuck
05/XJ8L

 

I had a similar issue recently and was only noticeable between 30-40 MPH. After checking everything on the drivetrain, it turned out the transmission mount needed to be replaced (there's only one). Here is the odd thing, it looked fine visually but apparently the rubber deteriorates over time and no longer provides the stiffness needed to work properly. According to a ZF Transmission expert, this is a common problem with Mercedes Benz cars that have the same ZF transmissions.

Hope this helps and keep us posted!

 

Have you checked the engine mount?

 

I had an annoying intermittent vibration sound that seemed to be coming from underneath my '04. I just discovered the source last week. The fasteners holding together the mufflers to the exhaust pipes ( located directly between rear wheels ) were installed such that they were in contact with what I think is the anti-rollbar.

 

Possibly a bearing issue.The drive belt tensioner is the usual suspect.

http://www.wikihow.com/Tell-if-a-Tim...nsioner-Is-Bad

 

Hi Chuck,

did you ever find find out what caused your vibrations?

Thanks
Hendrik