My work truck is dual fuel CNG. Ill check the mileage I get when I leave OKC tonight. On 16gge I can drive from Woodward to Alva idle for about 13 hours and get almost back to Woodward before I have to switch over to gasoline. I only notice power loss when fighting a strong head wind. The truck is a 2011 Chevy 2500 4x4 crew cab with a service bed on it. I was thinking the places around OKC that do conversions are in the 6 to 8k range. I think Oklahoma still has a tax credit on conversions