I was replying to this 10 minutes ago, but God decided to intervene with a heavy storm that knocked my power out.
Anyway, Danielle, this may or may not be what you are experiencing, but I have noticed my car doing something every once in a while. Basically, it feels like a jerk, but its being caused because just as the trans shifts to OD I hit an incline and it shifts right back to 3rd.
So basically, in under a second it goes 3 to 4 to 3 and makes a jerky, stumbling reaction. Hopefully that is all you are experiencing.