I have a post about almost the same thing in my 04 sxt and I have a auto thinkin about taken it to the dealer soon and mines had problems since I got it. Just a little hestation and when Im at a stop sign it lunges forward like the air is on and its not.

 

my mtx does that as well, dealer told me it was the rev limiter. only does it from first to second

 

Rev limiter my ***.....I'm never anywhere close to rev limiter when it's happened. In fact, when mine has done it, I was only between maybe 1000-2500 rpms. When it has ever happened to me, which is rare it is always below 3,000 rpms.