I would replace the fuel injectors as well. I had an issue similar a year ago and honestly what've now decided to do is, not necessarily throw parts at it, but if I find that there is an issue with say the fuel pump, then if the whole system is like 30+ years old then it all gets replaced. This isn't the same as throwing parts at it as you would already know what the issue is, but instead of just say getting new plugs, replace the entire ignition system like rotor, cap, and wires as well. On a side note, you might want to try tapping the airflow potentiometer on the side of the throttle body with a long socket. sometimes if that gets stuck or is off it will give the same symptoms that you are describing.

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1990 190E 3.0L