[Caddylackn]

I would go with taller tires first, before a gear ratio change, but stick to narrower tires like 65 series. Wider = more drag. Then run just below max. tire pressure, then compare mpg.

Check your mileage on a 30 mile trip against google maps and compare. I run a non factory tire size but I found my odometer matches perfectly, but my speedometer is off by 5%. Not sure how that happens. So my mpg is correct when I calculate it.