I recently purchased a 2006 Sonata V6, pre-owned with around 28000 miles. It seems like a nice, dependable car (I bought it primarily for my wife to use). One thing about its driving characteristic seems unusual, however, and I would like to know if it's common with this year/model; if anyone else has experienced this or if it might be a transmission problem. When accelerating from a stop at a steady increase in speed, the shift from 1st to 2nd seems to "lag", almost like there's a noticeable pause between shifts and for a brief second the car feels like it decelerates before accelerating again. The sensation is very slight and hard to really describe accurately, but it's there, enough to be noticed. I heard that these cars have throttle-by-wire and I don't know if that has any relation to what I'm describing. Does anyone have any ideas or comments?