If you ever owned a Saab 900, you'd know that what Kramer did made a surprising amount of sense. I suspect that there was a 1/4–1/3 of a tank left when the needle first hit the E and I also suspect that it was a misguided attempt to keep people from running out of gas, because the assumption was that people would refill on hitting "empty," but that they'd have a significant reserve in case there wasn't a gas station nearby. The problem was that once you figured out that E did not equal empty, you'd do exactly what Kramer did, especially if you were a dirtbag college student. IIRC, I once drove from BTV to Mad River Glen and back on "empty." I also ran out of gas twice. Sadly Keith Hernandez wasn't with me on either occasion.