It seems like there would be a way to do this, but I'm not sure how...
The only bump I've been able to get in the mileage on my '96 Suburu Legacy Wagon (auto tranny

)has come from wedging my foot against the tranny hump and trying to keep a constant throttle and let the speed fluctuate between 40mph uphill and 65mph going downhill.
It seems the cruise control could be rigged to do this too, any ideas?
********Update and pics are at the bottom************
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Mike
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"If you want to save gas I suggest you permanently remove the drivers seat and steering wheel. That seems to help." -Oscar Halverson