The '92 I just bought experiences an erratic, relatively loud buzzing/vibration-like sound from the front end of the car. It lasts for a few seconds , then stops. I can't feel any vibration and everything seems to work OK. So far, it has happened one time on each of the 2 drives I taken the car out for. It has happened both times within a few yards of taking off from my house. Someone suggested that it may have something to do with the ABS system. Any ideas as to cause ans remedy?