Hello, my Fiesta, 1,3l, 44kW/60PS, EZ 1996 has the following problems: If I start it cold it goes up to 2000 and then regulates it immediately down to approx. 900-1000U. If I drive it then it starts to turn up after a few minutes, on approx. 2000U and stays there. If Zünnung switches off and starts again, then it remains at approx. 1100 U in idle mode. If I pull off a sensor, e.g. the plug from the temperature sensor, then nothing changes at the speed, d I guess it’s in emergency run. Now I’ve changed the entire injection unit for a used one. However, I couldn’t change the throttle valve potentiometer, which is the old one without a plug. So I installed the old throttle valve potentiometer to the new (used) injection unit. Unfortunately, this exchange did not bring any improvement. I checked vacuum lines and cables, everything seems ok. Can one help me? Can one somehow make mistakes from Let me read with the engine? Do I have to change the other sensors gradually, like temperature sensor and then control unit? Thank you!!