My wife (girlfriend at the time) had an Oldsmobile Cutlass Ciera (with the 3.3L V-6) and we were able to squeeze a few mpgs more by filling up with premium gas. The transmission stays in overdrive longer when driving up hills, presumably due to greater knocking resistance. Moderate acceleration with quick easing after 40 mph also helped a lot. 35 mpg wasn't unusual in rural Idaho like that.
I miss that ol' mule. Best long distance cruising vehicle to date, although the vibrations over rough pavement always made me think something is going to fall off at any time, and the understeer in corners was quite worrying!
