I have a 2007 LS 460 since new and have had the same problem. The dealer has tried many fixes including resting my computer which worked for a short period of time. I kept bringing back to the dealer once it started again but unless you bring it in while it is happening and they drive it, they say they don't find anything wrong. I was able to bring it in one day which it was happening. It was happening during a very hot humid day. They took the car and make some adjustments one of which was changing over to synthetic oil. that worked well for a year till three weeks ago when I took it in for an oil change. This car has only 54,000 miles on it. It started that hesitation as I was pulling out of the dealership. I turned around and brought it right back I talked with the service manger an reminded him of how many times I have brought the car back for this problem. He kept the car for just over two weeks changing the cylinder heads and valves. I have had the car back for a few days and it runs better than it ever has. There is a Lexus Bulletin L-SB-0033-08 that talks about this problem. This is the fix but cost about $10,000.00 at the dealer. I was lucky to have an extended warranty. By the way, my amplifier and lumber seat motor went out a couple of weeks before.
Ihar
