Terriermom,

From the data you just told us, I would almost guarantee that you have the bug. If at 62 miles you averaged 39.1mpg - that means you used 1.58 gallons of gas to drive those 62 miles. If at 68 miles you were in the "high 40's" (I used 48 for my calculation???) that means that you had used 1.42 gallons of gas to drive the 68 miles total. You can't go 6 miles on negative .16 gallons. It is likely that your driving is consistent enough that your 'tank mileage' when you fill up is representative of your overall mileage (i.e. you drive the same commute over and over and don't do much else?) If this is the case then that would explain why your 'tank mileage' from the last reset till fill-up is the same as your calculated mileage.

Eric