I dont know if you solve the issue but I have had a same problem. When I pushed the gas, the car wasnt accelerated and when you stoped at traffic light, it was shaking like somebody pushing back and forth. If you have this kind of feelings with the car, go check the O2 sensors. My CEL was on and I checked and the code for each O2sensors was saying that O2 sensor was responding slowly. So I went to my mech and changed the O2 sensors. Now, I dont have any problem with the car since 2 years. It is strong, reliable. I love my lexus :)
