Its got a idle speed matrix, to speed up the engine when things are running, like AC, an load on the power steering etc. It is mentioned in the service CD. For starters get yourself the MB service CD, its $160 and covers wiring and trouble shooting 92-99 and owners manuals.
The car has sort of an electronic accelerator, dont move the linkage under the hood by hand while it is running, I have been told it will go into limp home mode (very little power from accelerator).