It's good to hear form xcel as he has had experience on a number of hybrids. xcel, you are in good company this weekend.
Hal Hidgon, who has done 111 marathons, is an expert on running economy (a runner's body behaves
a lot like an IMA - future thread). The Chicago Marathon this weekend is possibly the fastest/easiest because it's almost completly flat.
I expect the first few miles to have relatively poor fuel economy, as the engine and the cataylic converter are warming up. What suprizes me is noticing a harder time past those 1st few miles keeping the instant mpg readings over 75mpg (when the 5-speed Insight is in the lean burn mode). My guess is colder weather inhibits
lean burn. I would not be suprized if lean burn never activates in sub-zero weather.