|
Mixing and matching different EPA ratings is where you're getting off track. If you're using the 1984-2008 adjusted ratings, then compare the "old mpg", as it appears on the fueleconomy.gov site, for your F150 at 18mpg highway, to the "old mpg" of a 85 MT I6 F150 at 24mpg highway. I'm comparing the unadjusted ratings (download and unzip the stuff on the EPA site for those), which is the test result the EPA gets before adjusting it for more aggressive driving, and those are 23mpg for your truck and 30mpg for the 85. Either way, we're looking at a ~30+% difference in highway mileage.
|