Your harmonic balancer is in need of replacement. As you probably know,the balancer is a thick chunk of rubber sandwiched in between two steel rings.The problem is that with time the rubber gets very hard and dry. So it acts like an old bias tire when its cold it keeps its out of round shape caused by the belt tension. As the rubber heats up with the engine,it starts to become more elastic and quits wobbling. As time goes on 1 of 2 things will happen. It will split in two (if you have my luck, it will go directly threw your radiator with out passing go.) or it will cause the front main bearing and,or seal to fail. Try to get a new one as a used one will most likely be in the same shape. Terry A Shields 246 Old Indiana RD Blairsville PA 15717 ABBOTT@xxxx [Non-text portions of this message have been removed]