Steering wheel vibration/shaking. Random stuff...please help! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Hey all, I need some help. My car has been experiencing streering wheel vibration for about 11 months. If you are wondering why I never tackled the issue, I was gone for 5 months and the car was stored. Once I came back the problem obviously was still there. I took the car to the dealer (back then I had warranty) and they mentioned my rear tires were not completely round, something that can occur rarely. I figured I could live with it. Fast forward 3-4 months and now I just bought brand new rear tires, balanced and brand new front brakes (irrelevant I know...). I figured this could be great test to see if the vibration and shaking is gone. Unfortunately, this was not the case. Let me describe the symptoms: - Occurs only at fast speeds starting from 70mph and above. - Not only you can feel it but if I let my hands go I can even see it. It vibrates/shakes left and right. - The worst part is...it comes and goes! Sometimes it goes crazy then after sometime it relaxes and the steering feels great and as it should be... - Road condition does not seem to affect it, good asphalt or bad it can happen - Been trying to figure out if temperature has to do anything with this but I cannot establish a pattern. - Does not seem to occur at lower speeds at all. What the hell could the problem be? Along with my brake and rear tire installation I did a multi-point inspection. The car is GREEN everywhere but the dealer told me to pay attention to my CV boots. The car is a 2004 BoxsterS with 39k miles on it. I've been living for this for a while and I cannot stand it any longer. I thought my new rear tires would fix this but it is not. What could be the case? I want to take the car to the dealer again to tell him what to check. I do not have a lot of technical knowledge about cars so if anyone here can tell me what it could be I would greatly appreciate it.

Have you had the front wheels balanced? Sounds to me like you either lost a weight or have a flat spot. I'm not sure why it would come and go - that doesn't make sense to me. When I bought some new Gforce Sports, one of them was out-of-round from the manufacturer (never buying BFG's again!) and the sensation was very much what you're describing. I vote for taking your car to a competent shop that can do road-force balancing and find out if one (or more) of your wheels is out of balance...