Does it go beyond 100C? Not sure where the M119 normally sits engine temperature wise. Moisture is created in the combustion process and it sounds like it is being burned off. Continue to monitor coolant level. When was it last changed? Are you using the correct MB fluid? Not sure about the misfire. Plugs, filters, wires are a good place to start if they haven't been done in a while. Is your wiring harness original to the car?

__________________
1989 300CE