What you are describing is not normal at all.
I have no hesitation at all in the 35i X1, I dont drive it every day but one time it felt like the engine shut down completely for half a second when accelerating slowly and first thing I thought was HPFP. My wife has put 1200 miles on it and says she never noticed anything, she is pretty observant about how her cars run.
If its something that happens often and you got a CEL I'm sure the dealer will be able to figure it out. All it takes is one bad 10 cent part to shut a whole car down..