Had this happen to me on Tuesday . Start up ... jump to 4000+ surprised me , taped the gas once and it dropped back to 1900 rpm ,normal start up on a cold day.

 

At least there is some consistency in our cars!

 

The high RPM at engine starts below sub-zero celcius temps is part of the cold start logic improvements begining with the "M" flash. Another change was +3 seconds engine cranking before fuel injects into the engine.