intermittently loses power

The first time I lost power I took it right away to dealer. Car wasn't even a year old. Since they couldn't reproduce the problem they told me there was nothing they could do. Now it does it even more frequently and they still can't figure it out. When it "stutters" looses power it happens for a few seconds then engages and runs smoothly. It's happen in all gears at different times. While speeding, going up hill, driving on flat road. Hell even after driving for an hour non stop it will "stutters" but keeps going like nothing after a few seconds. Not sure what to make of it. Now I wonder if that has something to do with the fact that I can't get it smoged. It won't communicate with the equipment to get a read. So my 3 yr old car can't be registered. All that money for a new car and now I can't get it registered.