Id love to know also, i just purchased a 2008 KXS (55k ONLY on the clock) on the weekend from a well known dealer, the car started blowing white smoke also on start up, or under heavy load (ie climbing a large hill) I've taken it to the dealer who sold me the car, and we could not diagnose the problem. He said it would smell like sulpher if it were a gasket leak, and he thinks its water vapor .. Id agree if it only happens when it is cold, but seems to happen when you leave the car for 30+ minutes and then restart, hot or cold day does not matter. Also it left a belch of white smoke when climbing a hill recently, making me think its a little more significant. My local Toyota dealership cannot suggest what it might be, any help is appreciated!