hard chokes in between shifts???

i have an auto trans g2 seden, sometimes when i am holding the car at a steady speed and slowly decelerating still having my feet on the pedel the car sometimes chokes literaly, like something mess up or something anybody had this problem???? i know legends shifts harder that alot of other cars its a sports seden but this is not shifting it in between the shifts i cant figure out whats wrong, i heard something about the transmision rear mount, is that a wear and tear item, when do people usually replace it? have u done it yet.