Two issues with powertrain/transmission: 1- The powertrain/transmission fails intermittently- vehicle RPM gs sky high but vehicle receives no power, seems to fail/lose power. Has happened in very dangerous road conditions where unexpectedly was struggling to get the motor to engage/get power to the vehicle. Check engine and check hybrid system lights accompanies the problem. 2- The car should be driveable in electric only mode without use of gasoline. The powertrain/transmission seems to struggle to shift between electric and gas motors. HYUNDAI cannot seem to correctly diagnose or fix the issue. Ds not seem they have proper diagnostic process included on the car- despite finding error messages stored in computer, they initially said they could not recreate the problem and therefore could not fix. 3 different trips to Hyundai dealership repair center, in total they have had my car for 10 weeks. They have replaced the transaxle and sent the car home, but that did not cure the issue. They now have my car again. It just ds not seem they know how to identify or fix the issue. From online forums, I have learned MANY owners are experiencing the same problem and the same challenge to diagnose.