Low Idle/Stalling after adding oil

[aeciepli@undergrad.math.uwaterloo.ca (Avi Cieplinski)]

I have a '85 5000 CD Turbo Automatic, and I've noticed that it seems like
whenever I add oil to the engine to bring up the dipstick level, the car
will have a bad idle with a tendency to stall. This happened to me last week
and since I didn't know what was wrong, I took it to a local garage and they
replaced the idle stabilizer valve which seemed to cure the problem. But,
this morning I topped off the oil level and it happened again. The car lets
out a bit of oil smoke when I start it cold, but runs fine otherwise. I
asked my dealer about the oil smoke and he said that it was probably nothing
much to worry about and not worth spending the money to find out the
problem. I just chalked it up to worn valve stem seals, but now I am not
sure. Any ideas?

        -Avi