I have a 2015 Chevy Silverado 1500. Yesterday driving down the interstate with cruise control on I noticed the truck shifting back and forth between fourth and fifth gear. It seemed to hold fine when I would take the cruise off and hold the speed myself. It would also stop when pulling a hill as it would stay in fourth gear. Today it seemed to be doing the same thing in the lower gears and the check engine light came on as well. Planning on hooking it up to the scanner tomorrow but am looking for any ideas of where to start.
