Cal, your car does not go in a straight line from here to Florida and also at 6 to 10 thousand feet with a tail wind adding another 60 to 70 knots of speed and the mixture leaned out and the air being much thinner there is less drag. Your rpm level drops back and the engine does not work as hard plus the auto pilot like cruise control maintains maximum fuel efficiency. Oh yeah, pitch control for the prop helps as well. Hope that clarifies it and another thing, the 100% hi-octane fuel is more effecient too!
Threaded Mode