I found an aftermarket product online that is an ECU upgrade, and it
specifically addresses response issues.  I've been kicking around giving it
a try, but only if it is reversible.  Would sure love to know if anyone has
tried on on the 02 ES300.

Some time ago I mentioned that, after complaining to a Lexus service advisor
about my ongoing trans hesitation (well it really became a trans
jerking-while-finding-a-gear problem after last software upgrade) that he
mentioned that Lexus had issued a TSB that stated the need for premium fuel
after the upgrade.  I doubted it and he couldn't find the TSB. I later found
it online however, and he was right - it did state that. I still had my
doubts about fuel being involved.

Some here said that it was possible for the octane level to affect the trans
performance.  I finally gave in, and have been using premium fuel for the
past few thousand miles, and I have to say there is a big improvement.
Yesterday I felt the jerkiness again though - but it was a minor episode
compared to previous ones, and it was the first and only time since I
started using premium.

Now, it's kind of academic though, because I've been looking into getting an
'04 LS430. In doing my research on that vehicle, however, I learn that they
had a recall on those 430s made in '03 whereby the trans is replaced !  I
thought the worst thing on those cars was the air suspension.  Now I have to
worry about the trans on the LS430 I might buy !

Does anyone have any info on the 04 LS430 (6-speed) trans problem ?

(I suppose I should have started a new topic for this LS question.)