I am very confused by a front suspension problem that I am having with my recently purchased 98 gs400. Whenever I hit a bump in the road it causes a shutter in the steering wheel. To the point where after a longer drive it hurts my wrist from the almost constant vibration. This morning I replaced the front passenger side upper control arm because I had two mechanics that looked at the car that both said that was the cause of the problem. Needless to say the problem is still there. These lexus parts arnt cheap and would rather be purchasing some mods but needless to say this problem needs to be isolated. Anybody have any recommendations for me, anyone that has had a similar problem?

 

I would focus on the upper and lower ball joints (A-arms) or the steering rack bushings.

 

I had the same problem with my 2000 GS 300. You wouldnt beleive the stuff I've gotten done to try and remedy this. It appears to have been my struts that cause this sudden vibration. So far I have changes both struts,strut mounts, stabilizer links, control arms, and the bushings for the links, along with the rack and pinion. The only thing covered under warranty was the rack, and the ball joints. After getting this done, the car feel 95%, I still have to get an alignment tomorrow. After the alignment, and possibly new front tires (because bad struts cause uneven tire wear) I am confident that it will be "factory" new. Hope this helps. And also you can go to lexuspartsmall.com, it is a Lexus dealership out in California who specialize in wholesale parts, they are rather cheap. Call 262-797-2000 and ask for Kirk, he's the nicest guy. Good luck.