Two days ago truck was ok. But this weekend i needed to drive an hour to work and back both sat and sun. Total milage probably around 240 or 250. At the end of today getting off the highway, as she shifted fron first to second (automatic), she gave a kick then drove normally. Then i stopped, and then accelerated, and she gave another kick going from first to second. After this i also noticed my "service engine soon" light was on. Can anyone give me a clue about what could cause this?