2006 LS 430 erratic steering drift

[LS Lover]

I have a 2006 LS 430 with 151,000 mileage, which seems to have a problem with the steering rack and pinion or other suspension component that causes the car to drift back and forth from steering center position.  I have owned a 2001 and 2005 LS 430 and never experienced this type of unsteady, unstable feel which happens even on a smooth road, tending to drift off easily due to the crown of road, to right or left or an irregular place in pavement.

A general evaluation of the front end suspension components finds no defective worn parts, such as ball joints, rubber bushings, rod ends or swivels, etc.  alignment and tow in are ok.  What about the rack and pinon steering unit?  Is there any component adjustable for backlash or drag as in earlier steering boxes?   Or any other ideas or related experience??

Thanks!

Earl B

 

 

[RX400h]

Here's some reading that may include one or more reasons for the wander:

Curing Steering Wander (popularmechanics.com)