Engine Performance problem
1986 Mercedes Benz 300e 6 cyl Two Wheel Drive Automatic 170000 miles

I have problems with the car starting on the first try. It starts and when I release the key it chugs and dies. I start it again and have to press the accelerator down to keep it running. After it warms up it does okay but still idles hard.

Is this caused by the idle control unit or something else?

Thanks