since no-one else has piped-up, I'll tell you where mine is, ('92 300E so may be different), but it's located at the back of the driver's side of the engine, under the back part of the air-cleaner assembly, right next to the oil filter. The throttle linkages are here, and you'll see what looks like a bicycle brake cable, with a white plastic nut adjuster along it. I adjusted mine recently, and it made the car 'wake up'- what a difference.

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1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
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"music and women I cannot but give way to, whatever my business" -Pepys