low idle by cold engine, and uneven by warm engine... what in God's name is that? I've a w124 230e Mercedes from 1987. and after I changed the spark plugs my engine goes uneven and dies when it is cold. so I need to push on the gas so it runs at 1000 RPM...
somebody knows what this is? please give me some hints.

Check your plugs again, you may have a gap issue, or you may have damaged a lead removing it?