when i first bought my car the guy i bought it from put a new valve body in it and we changed the sensor by the tb not sure what its call throddle position sensor or somin not sure but my car will drive fine and when i brake it will jerk hard and get stuck in a gear and wont shift out of it till i stop and turn the car off and sometimes when on the high way doing at least 50+ the it just falls out of gear i have searched and found nothing on this problem any ideas on what it could be ideas on what this would be