Worn control arm bushings could be a possibility... Chased my problem for quite a while before figuring that one out. Being worn will allow alignment changes to happen as the suspension cycles up & down, sometimes sticking in a shimmy - sometimes not... Definitely take a real hard look at your tires though - get them balanced well - road-force balancer if possible; if not, make the tech use stick-on weights instead of the clamp-on as you can achieve greater accuracy. Also, if you're using Toy alum wheels make sure to get them balanced using a haweka adapter... They are lug-centric wheels, not hub-centric....

Been a while...<img src="/forums/images/graemlins/cheers.gif" alt="" />