Unfortunately, I am having the same ES300 problem. I m filing an NHTSA complaint as well and one with Lexus.
Oddly, I received a letter in the mail about a unique Lexus voluntary vehicle swap program at my dealer where I could get into a new vehicle without penalty and a larger vehicle at the same price. Do you think this has anything to do with this problem?
Considerring they sell more units of the ES300/330 than any other, I'm sure the loyalty stats might be at risk. Maybe they recognize this and will try to preserve this on a larger than "case-by-case" basis but smaller than a global admittion.
Joe
(ps: in my humble opinion, this annoying, but managble engine problem is not worth the trouble of a class action. statistically speaking, you either be out of your lease or into a newly owned car before there is a settlement.)