I have the same problem - low idle speed and bad vibration. My motor mounts are shot and I was sure that was going to fix it but after reading this thread I have new doubts. A couple of things:
Were the motor mounts Mercedes OEM? I've heard rumblings about the aftermarket ones not being of sufficient quality.
When I disconnect the idle control, my idle drops below 500 and the engine nearly dies. Does this imply that the "base idle speed" (if there is one) is set too low? How does one adjust this?
Can someone describe the "loosen the injector line" procedure in a bit more detail? Does it simply mean loosening the nut where the line goes into the injector? Doesn't this cause diesel fuel to spray all over the place?
