Check VSC and Check Engine Light

In November I took the car to the dealer after the VSC and Check Engine Lights came on. Prior to coming on, I could feel that there was something wrong with the car, sort of if I were driving on a bumpy road. Lights came on and the car was difficult to drive. I pulled over, turned the car off. When I started the car again the lights were gone and the car drove fine. The dealer checked and said that no codes were registered. However, since Christmas it has happened 4 times. The dealership kept it for a few days, drove it around, lights never came on for them, and no codes were registered. The only common denominator for the lights coming on is that it's always after I have driven it long distances and twice they came on shortly after filling up with gas. Dealership says that I should bring it in when the lights come on, but like I said, they only come on when I've driven about 60 miles from home. I am hesitant to drive the car. Have you heard of similar problems? The Lexus dealership had no answers for me.