2006 Grand Prix GT Transmission?

I have an 06 Grand Prix GT Supercharged with 45,000 miles on it. Ive noticed whenever im on the highway and i slow down considerably but not completely and I go to accelerate again, it almost jerks so to speak when I am trying to accelerate. Also, the other day I was getting into my car, I put it in reverse, I backed up and when I put it into drive to take off, it like sputtered or jerked and then started taking off. Does anyone know what this sounds like or have you experienced the same problem? I was wondering if maybe it could be the transmission? I have a feeling if I take it to the dealership they wont be able to duplicate the problem because it is intermittent. Thanks for your help!