Have a 2018 Optima. For over a year, it has been jerking when I break. An internet search says that a problem a with the transmission temp sensor is common in these vehicles and probably needs to be replaced. Brought it to dealer who said he could not replicate the jerking so he can't fix it. I usually have to drive the car at least 5 min, some times a bit longer for the jerking to start. Going back to dealer for regular maintenance next week. Any ideas on how to get them to fix it? It is really annoying and a real problem for me with a car that I like otherwise.