Is there something wrong with my transmission?

I have a 2004 Volkswagen Jetta 2.0 4 cylinder 4 speed automatic transmission with 67,000 miles. I was driving up a mountain pass today with the cruiseI have a 2004 Volkswagen Jetta 2.0 4 cylinder 4 speed automatic transmission with 67,000 miles. I was driving up a mountain pass today with the cruise on. When the highway leveled out the car quit accelerating for a couple of seconds. The speend dropped like 5 mph then it jerk really hard and sped back up. Then about two minutes later it did the same thing so I took it off of cruise and it was fine. Then I exited and came to a stop. I took off and it shifted through first fine but then when it went to shift into second it quit accelerating. I kept pushing harder on the petal until it was to the floor. It did nothing. It didn't rev or anything. It was as if I was not pressing on the gas petal. It was just idling at like 6 or 700 rpms. It was like that for about 10 - 15 seconds. Then all the sudden it took off. I parked it in a parking lot for like four hours. On the 125 drive back home it was fine. The drive back was going down the mountain. I am very concerned about this issue. It could be very dangerous.