I only had the car for about one week when this started to happen. I went back to the car dealer and told my sales man but he just said that maybe the automatic brake safety feature was making the car come to a uncontrolled jerky stop. However it continues to happen every so often when I am at a stop sign or stop light my car feels like it got hit from behind by another car but it’s the transmission possibly lagging and creating a sudden heavy jerk. The transmission also seems to slip periodically when I go from a stop to forward movement.