I am having the same problems as reported by owners of the 2006 model of this car. Initially car wouldn't start after 36 hours, and I had jumped. Again after sitting 36 hours wouldn't start. AA stated battery bad and replaced. Now the 4th time I had it jumped and took to my Lexus mechanic. Seemed there was a drain on battery while off, but undiagnosable after 2 days, with suggestion to replace with different battery and test present one. Feeling problem more serious, shop bringing car back to me when loss of power while driving. I will contact Lexus of Carlsbad where I bought car in 2011. I think this is likely a serious and costly problem unless Lexus will cover. My last Lexus, an ES, had sudden transmission failure while I was traveling and the outcome was not good.