[Mulder25]

I know there is a "lean-burn" on the Honda [civic is it?] but i had never read anything about a corolla.
The other day, i was driving home, up a slight grade. Not steep, but about 2 miles long. I started into the grade at 60MPH, my average economy was 46MPG and this was most of the way home. By the time i had reached the top of the grade, i was at 57MPH. My instantaneous economy, as measured by ScanGauge never dropped below 50MPG. This seems impossible, considering it was up a hill, and only a small drop in speed.
Has anyone heard if there is a lean-burn mode present in the Toyota Corolla? It is CE trim, 1.8L engine, 2001, and of course a standard transmission.