Yesterday I was driving from Las Vegas to Albuquerque for a class. My 260E was running like a champ. I stopped to fill-up at a Chevon. About a half hour later the engine started to sound rough and the economy needle went into the red and the Tachometer rpms also went higher. Gas mileage went form about 24mpg to around 10-15mpg !! Just starting the car the economy is in the red.