One problem related to engine stall has been reported for the 2018 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 Kia Motor Optima based on all problems reported for the 2018 Optima.
I purchased a brand new 2018 kia Optima in November 2018. I have put approximately 22,500 miles on it and have been keeping up with updated oil change maintenance per the schedule recommended by the dealer. On Saturday 9/28 I dropped the car off for a routine oil change, and as I drove it off the lot it sputtered as if it was going to die, but it didn't. The car continued to run and it got me home. The next day, Sunday 9/29, it drove without problems for about an hour, but while driving the car completely powered down and stopped working. It was a terrifying experience as I was in the middle of a major city road and almost caused a serious accident. I put the car into park and was able to start it back up, and I was lucky enough not to be struck by another vehicle. The dealership was closed at this time so I called them first thing Monday 10/1 to report the issue and dropped it off. The dealership is claiming to be unable to recreate the issue so ready to give me the car back. This is a huge safety concern and I can't believe we as consumers have to put our lives at risk to wait for the problem to happen again before any recourse can be taken. From my research on the internet, it is very common for the dealership not to be able to recreate the problem so unable to provide a fix. Kia had 5+ years of engine stall problems that were not acknowledged until many years later, and the dealership certainly will not validate this. Furthermore, when the engine stalls, the power steering and brakes both go out, so you have nothing but prayers to rely on to keep you alive.