While driving our 2011 Kia Optima on I-185 at highway speed, the vehicle suddenly had unresponsive accelerator and had decrease in power. Gauges were all normal range, no warning or indicator lights illuminated. I pulled over to the highway shoulder to clear traffic and placed car in park. Immediately light gray, then black smoke poured out from the hood. My wife and I evacuated the Kia just before the front of the vehicle was engulfed in flames. The engine had been replaced in Sept 2021 due to a previous recall, and up to this incident the Kia performed within normal parameters.