I have a Lexus ’07 IS250 and a few months ago, while waiting at a red light, my RPM’s dropped to almost 0 and my car started shaking like it was going to cut off. The same thing happened a few weeks later and has since happened a total of 8 times. I have taken the car to the dealer twice and they have found nothing wrong. I'm wondering if anyone else has had this issue and if so, what turned out to be the problem. If you haven't had the issue I'm open to any ideas about what the problem might be!! My dealership is pretty clueless and although I will admit I’ve had a quite a bit of warranty work done, I almost always have to diagnose myself. Thanks!!