Hi. 2020 A4 Avant diesel 35, auto. Have started to notice a vibration/engine labouring at low revs, started at around 28k. anyone else? same in all drive modes, efficient, comfort, auto. most noticeable at higher speeds + 50 and on inclines. I'm having to play with the throttle so it up the revs or it generates a gear drop down. was a smooth as silk before ;-(