Two problems started at the same time, they've got to be related.

At stop lights the idle will surge and if I'm not holding the brake hard enough the car will move, sometimes can be going 20mph at about 1300 RPM without touching the throttle.

If I turn on the cruise control it is erratic, like driving into waves of 70mph oncoming wind, constant pushing and pulling feeling and does make one sick.

Other than that, plenty of power and cruises the highway fine with manual foot control.

I was thinking the Idle Air Control Valve? Any opinions on that?

I need to fix this soon, because there is no way I'm driving 350 miles for Christmas without cruise control that does not make me sick.

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1988 Mercedes-Benz 300E W124 M103 California Emissions/Controller