Hyundai Repair: MY HYUNDAI IS FAILING IN PEFORMANCE, hyundai santa fe, throttle position sensor

Question
I HAVE A 2007 HYUNDAI SANTA FE 2.7L ENGINE. WHEN I TURN ON IT ON IN THE MORNING, IN IDLE RUNING WHILE I LOAD UP MY WORK STUFF INTO THE TRUNK, IT RUNS WELL BUT WHEN I START TO DRIVE, IT SUDDENLY SLOWS AND REFUSES TO RUN ABOVE 20M/HR AND THE ENGINE CHECK INDICATOR COMES ON THE DASHBOARD, THEN AN 'ESC OFF' LIGHT ALSO COMES ON... NO MATTER HOW HARD I PUSH THE PEDAL DOWN .. WHEN I PARK BY THE SIDE, TURN THE ENGINE OFF AND TURN THE ENGINE ON AGAIN, IT MIGHT NOW RUN PROPERLY AFTER SO MANY TIMES OF TURNING THE ENGINE ON AND OFF AND ON... PLS HELP

Answer
Your symptoms are consistent with anything that will prevent the electronic throttle from working properly.  The most common failure is with the throttle position sensor.  If this is the failure, you'll need to take the car to the dealer, as Hyundai has released a technical service bulletin instructing dealers to replace the throttle position sensor and reprogram the engine control module.  Whether this repair would be covered under your new vehicle warranty will depend on whether you have exceeded 60,000 miles.

Of course, there's no way to know the nature of the problem without reading the stored diagnostic trouble codes, so the above is only speculation.