Well i got the car back yesterday. A valve in the throttle body got stuck instead of opening and closing as it should apparently. Anyways it got cleaned out and lubricated and problem went away.
What i do notice is that the car is so much more reponsive than before. Another thing i noticed this morning was the rev counter when the car is started from cold. I have used a 4 cars before buying the IS, on every single one, when the car is started from cold, the revs start quite high 1500rpm and then gradually go down to 500rpm once the engine warms up.
Before the trip to the Garage, my IS when started from cold goes straight down to around 350-400 rpm, but now it behaves like all the other car's i've had. I thought it was a lexus thing with the low rpm at start up so didnt think too much of it.
How does your IS behave at start up?