C63 amg 2013 rev needle jumping

Hey!

I have been on a google nightmare and cant find any answers on my "problem"
I bought this car about 2 month ago and I starting to notice that the rev needle is jumping up and down while driving. For example;
I drive on a flat highway, set speed limiter at 110km/h (60mp/h) and I notice rev needle keep going 1800>1700>1800>1700 etc. Is this normal? If not, what can cause this problem?
It have recently been through a full service at mercedes, new oil etc.

I have also noticed when ive stoped with car in idle, that sometimes, rarely thought, I feel a quick shake in the car. Like the engine shakes for 0.5 secs. Feels like the car "moves". I thought it was because of that massive engine, but now im not sure. Ive tried calling the car dealer but the seller is very hard to get in touch with. Telling me to call back later etc.

I got summer tires on and its minus outside so can't take it anywhere at the moment, but I have s video of the rev jumping if it will help.

Cheers!