One problem that can lead to a malfunction on the Mercedes W124 230 CE (´87) is a broken spring on the throttle return.
If the accelerator pedal is not pressed, the small spring ensures that the switch is actuated to detect the overrun cut-off. If this spring is no longer present, the car no longer recognizes the situation of the thrust operation correctly.
Because of an idling problem we took a closer look at the throttle linkage and noticed that the mentioned spring was no longer present.
As it quickly turned out during research, this feather likes to rust and breaks at some point. Another well-known defect is that the eyelets in which the spring is inserted wear out at high mileages. This has to be repaired a bit more laboriously (welding or screw constructions etc.).
The problem hasn’t progressed very far with us yet. Only about 0.5mm the spring has eaten into the metal. But with a mileage of 250 000 km so far, there should be some room for a few more years.
The small spring has the part number: A102 993 09 10 and is available at Mercedes for only ~4€ incl. VAT.
The installation just couldn’t be. Hook in the spring and you’re done!
Now the tension of the spring ensures that the microswitch of the thrust cut-off remains pressed until you put your foot on the accelerator pedal. One problem less!