When the car encounters a hill and needs to downshift, either to climb or to hold back the speed when it descends, the cruise control remembers the downshift and will not return to high gear until a) it is manually overridden, but will still downshift up to 2 gears, when the lever is placed back to automatic or, B) when the cruise control is turned off. The cruise control also belatedly reacts to loss of speed control and overcorrects with too much power, resulting in a crude ride, as well. The workload is increased dealing with getting the car to attain top gear on flat roads, and is creating unsafe conditions, in my opinion. I have attempted to get this attended to at the dealership, and they continue to not fix the issue, as well as inform me I shouldn't be using cruise control on hills. My 2014 Kia Optima did not exhibit these issues, nor any other of my cars which had cruise control. There is a problem and these people will not fix it. The consumer stated the heat does enter the foot well area.

- Ocean Park, WA, USA

I have been experiencing issues with my 2016 Kia Optima since I purchased it on September, 5th 2016. A short time after owning my new vehicle, first the car started to hesitate when starting as if it was struggling to start, the push button would turn red and the indicator lights would light up on the dashboard as if the key was not recognized in the car. The car would also self accelerate. On or around August 16th or 17th the car stalled out while it was being driven, we attempted to restart the car and it turned on like normal so the tow was canceled., the service writer & Kia all have copies of the videos the mechanic has also told me he was able to duplicate the issue, the solution was to change the fuel pump and service the fuel delivery system. Upon the services being completed we were contacted by the service manager, and Kia that the car was ready to be picked up on September 6th 2017. While driving the vehicle home we noticed some hesitation while idle, also some strong acceleration when taking off from red-light or stop sign. While parked we noticed some strong vibration from the motor which the car had not had previously before service. Also after several attempts of starting the car, the car would either start rough, and also still had the same original occurrence as before with the key not being recognized in the car. With the car not fully starting and the push button turning red with the instrument panel lighting up with the key not in car light along with some others. On Thursday September 7th, 2017 at about 4:30pm I had the cruise control set to 80 mph, the car hesitated a couple times, then self decelerated to 73 mph, reaccelerated to 82 mph then self adjusted to 80 mph, I contacted the dealership right after the occurrence I was told I had to wait to bring the car back in they had no loaner vehicles, not to use the cruise control feature.

- Melbourne, FL, USA

Since I had the car in aug2016 brand new when I give it gas the valves ping and peak extremely bad not matter what fuel I use also the ac keeps loosing power it will blow fine then it almost goes off while still driving the same speed. Also sometimes when this happens I have a miss or hesitation in the engine. There has also been a pop noise in the back end when I stop or slow down since I have had the vehicle. I have taken my car 6 times to the local dealer in chas wv where I purchased the car and they keep saying they can't dignose the problem they have to contact Kia and never have an answer wheh I take the car back or contact them.

- Charleston, WV, USA

The contact owns a 2016 Kia Optima. The contact stated that the vehicle had a few seconds delay in acceleration. The contact took the vehicle to a dealer where it was diagnosed that there was a sensor delay. The manufacturer was not notified of the issue. The failure mileage was 200.

- Spartenburg, SC, USA

The contact owns a 2016 Kia Optima. While driving various speeds, the vehicle accelerated independently and the engine rpms drastically increased to 6 or 7. the contact also stated that the check engine warning indicator illuminated and there was a burning odor coming from the engine. In addition, the vehicle was leaking oil. The vehicle was taken to the dealer where it was diagnosed that the cvt valve needed to be replaced. The dealer stated that the vehicle was number 75 on the waiting list for the repairs and provided a loaner vehicle. Two days later, the contact was informed by the dealer that they performed an interim repair and that the vehicle could be driven. The dealer ordered the part for a permanent repair. The contact felt unsafe driving the vehicle. The manufacturer was not notified of the failure. The failure mileage was 1,000.

- Pewaukee, WI, USA