Hi; I am new to this forum..I just purchased above model and have done less than 500 miles I ask the same question to Lexus local dealer according to him its normal...so just for my further satisfaction I want to throw this question to all my latest friend in this forum. Let me explain while driving in traffic jams where you can not exceed 5-10 mils per hr speed I feel cars starts jerks its not smooth at lower RPM its like some one is pushing you with intervals..is this normal for a rear wheel driven car? Please help me to understand the situation. thanks and regards