Friday morning I'm backing my 2011 Sonata Limited out of the garage and I always idle out but this time it started backing about 2 paces faster than idle speed. I hit the brakes and the pedal is on the floor..no brakes..I put it “D”rive and nothing no power. It didn't stop until I backed into the street curb, tires only no damage. When it hit the curb the brake pedal was back and “D”rive engaged as if nothing ever happened. Dropped it off at the dealer and they couldn't find anything but did open a case with Hyundai. Saturday doing a couple of backing the brakes were really spongy in reverse only. Will have that checked next week.