When I am in a any gear it seems when I push the gas it jerks and when u let off the pedal it will jerk again...u can feel it big time using the gas and then letting off it will go back...it's hard to explain but I'm trying..also it will kinda get confused and jerk over and over until I give it more gas or put in neutral...what could this be?

 

mechanic siad it could be the deceleration valve..but im lookin at forums and i guess it coul be the IAC or the throttle pos. vavle...