Tank Assembly problems of the 2008 Lexus LS460

I drive Lexus 460 LS. It has 30,000 miles with a recent service. On the day of accident , I was driving to work at 7am. I had gas tank filled up the night before. The car started jerking when I left the house. A warning light came to take the vehicle to dealership for check up. Since the dealership was on my way to work, therefore I decided to go ahead and drive. After 10 miles the car started to stop and I was barely able to take an exit and stopped at the curb to avoid some one hitting me from behind. My car was towed to Lexus service station and I was told by them that gas was either diesel or had high contents of ethanol. I called florida better bureau. They analyzed the gas from the gas station and I was told that there was nothing wrong with gas. The dealership has refused to take the blame that there was a major engine failure. I wanted to bring this incident to your attention and wanted to know if some one else has reported a similar mishap. I want your department to investigate this accident so that it does not happen to any one else. I was very lucky to escape a life threatening accident but some one else may not be that lucky. Lexus should be held responsible for the engine failure. Thanks for your help.