My 2006 Lexus rx 400H has experienced a vibration during acceleration. It seems to stall the engine. Bring the vehicle to dealer for checking. The dealer said my vehicle uses incorrect grade of gasoline or not good quality gasoline and recommend that I shall always use better quality gasoline, I.e. gasoline from shell. The vibration is caused by the misfire. Subsequently using the gasoline from shell and the vibration seems to be reduced or go away. Later on, try to use a different brand of gasoline (same grade, premium) and the vibration comes back. It seems the vibration has something to do with the timing of ignition which is controlled by the computer. It does not make sense that the design of computer software modeling is based on certain brand of gasoline or the design margin is so tight that the ignition timing does not work with the gasoline that is slight deviated from the gasoline that Lexus uses to make the design. If I drive the car long distance or out of town and can not find the gas station that sell the gasoline which produce no vibration, then, I could run into a serious situation that my vehicle could be stalled or broken down due to severe vibration.

- Bellevue, WA, USA