rough running on cold start

[Manolito]

'97 328i automatic, 140k miles (different e36 from my last two questions)

Car is clear across the country so I am trying to diagnose over email.

Daughter has complained of rough running after cold start for weeks. As the weather turned colder, this has degraded to the point where she can barely keep it running after a cold start. After a few seconds if she turns it off (or it stalls out) she can restart it and it is immediately much better.

This is not a problem I have experienced or read about before.

One other factor that may be related - when I did the VANOS O-rings last year, there was a lot of varnish on the sliding surfaces that I could not really get off. I cleaned and polished it as best I could, but the VANOS did not move as smoothly and easily as the one on my other e36.

The only code stored is for a misfire (no kidding).