I trust the trip-odometer. When it gets over 300 miles on the Fiero, it's time to fill up. 320 miles is about the max I'm willing to go.
I've noticed that I get better MPG during and after a rain, and with non-ethanol fuel. My truck, for example, was driving down the highway, at 60 MPG, getting about 21 MPG, for the 50-mile average. It started raining. Not enough to turn the wipers to high, but enough to have the wipers on steady. The MPG dramatically increased, such that, 2 hours later, the 50-mile average MPG increased to 24.
