For some reason I had never thought to reset the mpg gauge to see how this car really does in city driving, so today I did, and the car indicates I was getting an appalling 20mpg while going through the stop sign ridden streets of SF, despite not exceeding 20mph and killing the engine diligently at lights. My MR2 could do ~25-27 under similar conditions. The extra 600lbs seems to be quite a burden.
That said, this morning driving up 101 into the city the computer said I averaged 40mpg, and I was doing a steady 65 with no engine off coasting. Seems to validate the 45mpg trip down as not being due to elevation change.