Newbie Question about the motor when driving ...

I'll take a shot at this and say, probably normal. The ICE will shudder sometimes when it shuts off, until it gets up to operating temperature. The "stalling" could be the traction control kicking in. If the wheel(s) are slipping upon acceleration the traction control feature feels like the power is cut off, then it recovers. (If the wheels aren't slipping, then there may be another problem.)
Others, feel free to jump in!

 

Normal.

"Stalling"? The engine deliberately shuts itself off when it is not needed and re-starts itself when it is needed. It does this many times while driving. Is that what you're noticing?

 

:welcome: Welcome to PriusChat, cuong32!
I'm pretty sure it's normal. A new Prius shuts down the Internal Combustion Engine a little harder than one with a few thousand miles on it. The ICE doesn't just stop, the electric motor moves it to the place where it will start again the easiest. If it misses the spot the first time, it goes through another cycle to get to the right place, this causes a shudder which may feel a little like a stall. I bet you won't notice after your first oil change.

As for the lunging, this too seems to be a new Prius phenomenon. The Power Split Device is always engaged, so the car is never out of gear. A new ICE may start a little more forcefully and give you a little rocking. Don't worry, enjoy!