im simply driving? My Chrysler Lebaron is a 1991 and it will randomly try to down shift/ jerk when i am simply drivin on the highway. the high is where it seems to do it the most when i am goin around 70-80 anywhere in there. I dont know if the jerking is because it is trying to down shift. i have had it die before when it started one of its fits. it has had new spark plungs, wires and distributor cap put in it. would could be the problem????