OM651 4cyl rough idle cold start

The last few days, I've had a rough idle at startup in the morning. Feels like it's running on 2 or 3 cylinders. It goes away as soon as I drive off, but will last about a minute or longer if I just sit there and idle after starting. Fine the rest of the day.

Thoughts?

Year, miles, any codes, CEL? How is the vehicle driven, daily, weekly, monthly, city or highway.

BTW, no need to idle stationary to warm-up, drive immediately, but take it slow and accelerate slowing until engine reaches operating temperature. The Sprinter has a sophisticated cooling system.

2016
122,000 miles
no codes