I explained to Lexus customer services today that quite a number of people have experienced this issue in the States and they have had their ECU flashed. I believe some of their issues have been down to a noisy fuel pump too and it supposed to have enhanced their driving performance, in what way, I do not know. The Lexus UK division say they are not aware of any TSB's on this issue or anybody else experiencing the same issue within the UK. I truly believe, this is inherent in this vehicle and would never have traded in my ISF if I had been made aware of this issue with the car. If it is part of the make up of the car, why isn't this made clear to any potential buyers as this major flaw could well influence a decision to buy the car oil the 1st instance; it would of mine, anyway.
I have also had this in Sport mode too. When I have been in Sports plus, just over 70 miles an hour, it hasn't held itself in high revs, it has dropped down to 2000 revs and then when I have put my foot down again it experiences the delay too.
Have you mentioned this to your dealer too please??