Formeister

How old are your tires? I've had serious delamination problems with steel belted tires in the past. Take your wheels off and check them. You can't always see this with the tires on the car.

Here's a link I found that worked for me: http://www.lexustsb.com/categories/Lexus+IS/IS250+%7B47%7D+IS350/ Click on the TSB and then scroll down to open the .pdf for details.

Wondering why this topic is pinned as it has no usable information or links.