If I burn my entire 19.5 gallon tank at 66-67 real world mph i can go about 290 miles according to the odo, which is ~14% less than what it really is, due to the tires and uncalibrated speedo/odo. The 58mph that the speedo says is actually 66-67, 14% higher (I have gps). So actual miles driven, all highway at that speed, is about 330, or 14% higher than the 290 the odometer reads. 17 mpg.
Add any city driving to that and the number goes way down. All city I get about 12 driving nicely.
Its impossible for me to accurately calculate actual miles driven on a tank in the city, due to the constant speed changes. (the faster you go the more inaccurate the speedo is)
EDIT - I have no idea why I just posted this in the 3.0 forum.
Last edited by gts007; 04-14-2010 at 07:01 PM.