My W124 230CE is powerless on high rpm's. Present top speed is about 110 km/h. Think I have checked almost everything. Exhaust system from kat and back is changed. Fuel pump and filters are changed. I have tried a lot of second hand parts: Fuel distributor unit, control unit, potentiometer, lambdasond. I have cleaned the injectors. None of these changes has made any significan diffrence. The kompression and the preignition is ok. I'm out of ideas. I hope you can give me some advice