Now that the weather is cooling down in Minnesota, my 87 300TD is running rough when I first start it up and particularly when idling in neutral. Perhaps a little extra diesel smoke, as well. I always use premium diesel of at least 45 cetane. The car just has 66,000 miles on it and I think the injectors are original.
Also, I had the car to an MB dealer in July because it was dieseling. I thought the shut-off valve needed replacing. They said the vacuum lines needed cleaning out and it did take care of the problem. But now, 2 months later it is doing it again, although not as bad. Before, I usually had to push the stop button to turn it off when it was warm. Now, it just runs on for a few seconds.
Does it sound like I have two unrelated problems, or one that is manifesting in more ways now?
Thanks in advance for any input.