On my 18th birthday I got a car loan and flew one way from PA to North Carolina. I bought the car and drove it 8.5 hours to PA. This was on Saturday. Now it is Monday and over all my average MPG is only around 45MPG. I don't speed nor do I have a lead foot. I have checked the tire pressure when I bought it and all tires were 30 and under. I pumped them up to 38 in the front and 35 in the back. This didn't change anything. I do not have the bridgestone tires on it. It has sumimoto tires. The insight is an automatic with 100,000 miles on it. I am a sensitive driver and have tried numerously to achieve lean burn mode. Is there a video tutorial explaining it? Is there something wrong with my car? It is great exterior and interior condition. Please help...?