rpm

Anyone have an idea whats happening with my Q50. Its a 2018 3.0t a lease still under warranty 18,900 miles. Its been sitting about a week, the weather has gotten cold. After warming it up a little i took it for a spin late last night and i noticed it was not taking power like it normally does...

Upon cold startup, what happens is the RPM needle will just sort of flicker meanwhile the speedometer needle will do the full swoop "needle dance" (When the needle goes all the way up and comes back down). This happens during a cold startup but very random afterwards throughout the day...