Is anyone else obsessed with fuel economy?

[3Diesels]

Every time I fill the tank I reset the trip meter (in all vehicles!). DH does this as well, but only due to my nagging him. When I'm driving down the road, I'm constantly looking at the fuel gauge vs the number of miles on the trip meter to determine if my mileage is ok...I've analyzed in my VW that I need to get about 80-90 miles per "notch" on the gauge (there are 8, not including empty) in order to have at least 45 mpg...In the Mercedes I'm still analyzing...the gauge seems less consistant, and there are fewer "notches". But, I figure I should be at 200-250 by the halfway mark to be at 32-35 mpg for a tank...If we're on a trip in the truck, I'm constantly asking how many miles and where the gauge is (I am not "allowed" to drive the truck often LOL). We have a computer in the truck that tells what the avg mileage is, but it is slightly off...It usually reads about 2 mpg below what we figure by dividing # of miles by gallons at fill-up.

When we went to buy a new car (the VW), I did a spreadsheet with the initial cost of a vehicle vs the fuel cost over 10 and 20 years (assuming that each vehicle would last to a certain mileage, and that we would drive a certain amount of miles per year) to figure out the least expensive car.

I think I need a life I actually look forward to filling up, though I don't get to do it that often. I've been this way since my first car (VW Bug)...it got 40 mpg+ on a good all-highway day

Cathy