Going through this with my'17 now. Plugs and wires were done last year, changed the tranny fluid and a few months later I am looking at rebuilding it. Also installed new fuel pump as the pressure was a little low but not bad. Still not that much improvement. GMC shop is telling me the misfiring is from the tranny slipping. They can't tell me exactly what it will cost other than 2000.00 in labor plus parts.
Thinking I will just trade it in and stop throwing money at it hoping this issue goes away.
