I think I know what your referring too, when I would be going at a fairly high rate of speed(80+) than slow down, it wouldn't stop as fast as you'd think it should, it would kind of pulsate and take longer to stop when you would think it should be alot less for the car your in. I had 2500 miles on mine before I traded it in. It was one of the many complaints I made when they called for the phone survey after purchase...