Unexplained vibration!!!
 

After having my 2001 X5 (3.0) in the local shop for the last 2 weeks and having all motor mounts replaced and then having the transmission mount replaced........I still have the exact same problem!!! Hopefully someone can chime in with any possible ideas/solutions.

Here is my problem:
The car seems to run perfect except when I am stopped and in gear. There are no check engine lights on, etc. The problem is only when the car is in gear and I am sitting stopped at a light with my foot on the brake I have a pretty strong vibration. My steering wheel, drivers seat, passenger seat, floor, etc. are all vibrating like I am in a massage chair! As soon as I put the car in park or in neutral it goes away. Also, as soon as I start driving it goes away. I does not vibrate at all when driving. It vibrates the same when stopped if I have the air conditioning on or off.
The shop first said it was motor mounts. I had all motor mounts replaced $$. Went to pick up the car to drive off and noticed I still had the same problem. I was then told it has to be the transmission mount. I had the transmission mount replaced. Went to pick up my car and still have the same problem! I really don't know what to do from here. Any ideas?

Once I had a vibration due to the air idle control valve. Not sure if that will help. It seemed to only vibrate in certain conditions. But I replaced it and problem solved. The valve flap had broken off.

Try this, when you're sitting there at idle in gear with the vibration happening... try just barely hitting the gas to raise the RPM only 50 to 100 rpm. You'd be amazed what a difference a few RPM makes at idle. If that does indeed smooth it out you could ask the dealer to raise the RPM by 50 through a test plan in the diagnostic equipment. I've fixed quite a few BMWs with the same vibration at idle doing this.

Thanks for your help guys. I am going to take this info to my shop tomorrow. Will let you know how it turns out.

I've done this exact thing on motorcycles - if you can't find the source of the vibration, change the idle speed!

Idle speed has to go up a lot for it to work
 

In my case, I tried holding my foot on the brake and giving it a little bit of gas, but in order to get rid of the vibrating I have to give it enough gas to raise the rpm's by approx. 400rpm. I don't think I would want the idle up that high!