I have a 2002 Kia Sedona. Periodically (say 1 out of every 3 times I drive it) the brakes drag and rotors get really hot. When this happens, I notice the brake pedal is super sensitive. Brakes work fine and car stops fine, but brake pedal is hard. Brake pedal barely moves, but with very slight movement the brakes brake hard and car stops fast. When the brakes are working " normal", the rotors are just barely warm to touch after driving, but brake pedal moves at least half way down. Much more travel in the pedal. What could be causing the brakes to stay stiff/drag and be causing the brake pedal to hardly move and be super sensitive? I've had KIA dealers looks at it and they say they can't find anything wrong.