Switching to diesel fuel is one of the single greatest modifications a driver can make to dramatically improve their fuel efficiency. Not only does the fuel pack 18% more energy than conventional gasoline, but the design of diesel engines provides more torque at the wheels. Jeep Wrangler owners everywhere will soon rejoice when Daimler Chrysler officially begins to sell crate diesel engine kits for TJ owners (covering Wranglers from 1997-2006). The kit makes use of the reliable 2.8L CRD utilized in the Liberty but with a modification to remove the lone troublesome component, the exhaust gas recirculation unit (EGR). Even with the price of diesel reaching above $4 a gallon, the fuel efficiency improvements still provide a cheaper cost per mile than gasoline priced $1 less. Perhaps if the popularity of diesel engines continues to spread across the United States, it will become cost effective to construct additional refineries to stabilize the price of diesel. Furthermore, diesel engines can generally run bio-diesel directly, (which packs 50% more energy than ethanol and can be made from a larger pool of sources) allowing the nation to transition to alternative fuel without significantly altering the delivery infrastructure.