Car Accelerates On Its Own problems of the 2012 Chevrolet Cruze

While driving my new chevy Cruze I have noticed that once in a while I will go to accelerate and the car will not go. I'll get to about 20mph and it's like the car doesn't know I'm pushing the pedal to accelerate. I can tell that is getting gas and that it's not the transmission because it doesn't make a sound. It just stops at about 20mph and doesn't go any further until I put the pedal down further, doesn't go, then a little more then it suddenly accelerates and jerks because I have the pedal down so far. I've seen other complaints on the website and I believe it is due to a faulty tsp sensor. My dealer cannot find the issue because they can not make it reoccur and the check engine light does not go on. The last incident that happened while I was merging on to I-55 south and as I was merging my car would not accelerate with a line of cars behind me and a line of cars on my left. Very scary. When I asked my dealer what happens when I get into an accident because of this I was just told I hope that doesn't happen and when it happens again to bring it back.

A sudden acceleration of the engine.