Does it go back to normal if you slow down considerably? Sounds like it might not be getting enough fuel. Symptomatic of a clogged fuel filter or a failing fuel pump.
Ask the dealer what oil they put in it. If you are ok with it, then fine. Personally, I would change it and put in full synthetic, and consider the dealer change a good flush of the system.
Something like that happened to me. A quick restart had no effect, but being off for a while (in my case, an hour) did the trick. That was in September, and it has not occurred again.