Is your mil light on?

Whats your temp needle read when this happens?

That doesnt sound right to have 1 bar at idle. Did you have the oil pressure reading taken?

You may have a misfire somewhere. Pull one spark plug at a time while the car is running and apply to the metal so you dont get shocked. You will be able to see if you are getting spark. Also if the motor behavior doesnt change when you pull then you have found part of the problem. The motor should almost start to buckle when a spark plug is pulled.

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)