I had a weird experience with mileage issues a couple of days ago. I had about 50 miles on that tank and the indicated 'Range' was 381 miles. As I drove the elapsed odometer mileage climbed but the range didn't move off 381. After about 20 miles suddenly the range began dropping rapidly, about 5 miles per second: 380-375-370-365 etc. until it bottomed out around 200 miles of range left. And this is with over 3/4 tank left. After a couple of minutes the range popped back up over 300 to the correct setting. I don't know if this 'hiccup' is common, I have never seen it before but maybe it has done it in the past w/o me watching the instruments so closely. Not a concern to me, just an oddity.