Sonata I45 (LF 2015+) :: Hesitation Upon Acceleration And Check Engine Light Came On

I bought a pre-owned 2015 Sonata Limited in November. I only had less than two weeks before the car hesitated upon acceleration and the check engine light came on. At the time, I thought it was a loose gas cap as I'd just gassed up. I took it to the dealership, they pulled the code and it said to replace the accelerator pedal. That required a second trip to the dealership 2 weeks later when they completed the work. Two weeks later and the light came back on. I took it back and asked them to keep it until they found and fixed the root cause while I took a loaner. They kept the car about 2 weeks and when I picked it up, I found that no work had been completed. Two days (!!) later the light came back on.