I have a 1993 300e 2.8 and the throttle body is making a whining/buzzing noise. It kind of sounds like an electric motor running. It does stop when the throttle body wiring is disconnected. This can only be heard with the ignition on but with the engine not running. It may still be making the noise but is not loud enough to be heard over the engine. Is this an indication that it is going bad?

Thanks for any help

The buzzing noise is normal. I believe it is called dither. It increases the control in electro-mechanical systems.

Good news. Thanks.