I'm pretty sure it's a quirk with how Toyota reports something or other to the OBD port. My sister's 2002 Camry reports the same 0.02 gph any time the ignition is on and the engine is off. Climb in, click to on but don't start it, and it's already reporting fuel usage.
My Civic and Odyssey, on the other hand, will both report 0 gph every time the engine is off. My mom's nissan truck as well.
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11-mile commute: 100 mpg - - - Tank: 90.2 mpg / 1191 miles
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