Ok so about 4 days ago i filled up my tank with premium gas. I only drive to school and then to practice so i only get to about 60 mph. I had gone 200 miles and the gauge said i had half a tank which i thought was amazing but then i only got 75 miles to the last half. Is this usual for any of you guys?? I take off anywhere from 2500 to 3000 rpms and i shift around 3k as well so im not really running it hard. Can someone help?