When the engine’s cold, my car (Mazda 6 Station Wagon) revs up when I first turn it on, and then acts like it’s going to stall out right away. I have to rev up the engine a bit for it to come up to a normal neutral state. Afterwards, everything works normally. When the car’s still a warming up, though, it does seem to hesitate a little before kicking into first gear.
A couple of notes, I just replaced the transmission on the car at the beginning of the year. It was a refurbished piece.