Okay... this is weird. So I've been driving carefully, staying at the speed limit or within five miles per hour of the last two tanks.
I've been getting 35-36 mpg by doing this.
Today I went to the Beaverton, OR Honda-Tech meet. I left my house and got to the gas station in town just to find that I'd forgotten my wallet at home, so I had to race home while Eran, my boyfriend, waited at the gas station and grabbed something to eat.
I got back to the gas station, filled up and we went to the meet. We both gassed back up once we got back home.
Somehow on that first half a tank I got 3.735 mpg. Not far over my recent average, but not what I was expecting.
Then it gets weird though. For my trip to the meet we averaged 75-80 mph. The trip back we went closer to 60-70 mph. I got 41.25 mpg for that half a tank.
I'm still surprised. My car's a '98 EX coupe, manual btw. It needs a tune up still (wires still have never been changed in five years since I've had it, could use an oil change and some new plugs, maybe a cap and rotor for the first time in five years too).
Maybe I should just go 80 everywhere.