Welcome to LOC and welcome to the IS220D. I'm afraid it's a "feature" with the 220D. Lexus did release a sport (which I have) which cures it. Its basically down to gear ratio and I'm afraid there aint much you can do (apart from adjust your driving style).
When I first test drove a new one (2 years ago) I spotted this issue straight away when approaching a round about slow in 2nd, I nearly got smacked in the side by the time the turbo had kicked in. I then did some research before going to a BMW, but as of 3 months ago got a Lexus. I knew it would either have to be a sport or a 250 auto and the sport came along at the right time, price, colour etc.
Definatley theres a issue with the 220d gearing and i have taken the advise of other members and changed my driving style.
If im honest I now drive it like im driving the mrs 1.2 corsa and it seems to drive mint now. However I agree this cant be any good for the car or the mpg. you would think a 2.2 d would have a better gearing ratio than this.
I would have expected better from lexus.........