Ive got a similar problem with my w201. Besides the obvious. it struggles to start up on cold mornings, but after a few attempts it runs fine.

But last night I had noticed a rough idle when I pulled in late at home, the idle was aggressive shaking at low revs, almost felt like a cylinder wasn't firing. This morning went to start it up and wont turn on. I also noticed my fourth injector line at the pump is very wet (with diesel) but I checked to make sure everything was tightened down. Smoke starts to appear after cranking long, my guess is the hot starter evaporates the diesel that leaks out from the line.

Any suggestions guys would be great.

PS its a 1984 190D 2.2L