In case you are thinking I'm insane over the Excusion getting high MPGs, it is because it is simple and cheap to convert any diesel engine to run on vegetable oil. There are few who convert diesels, but SUVs are in luck as SUV and heavy-duty truck diesels are more common then compact diesels. We know a family who has had their diesel Expedition converted, and they've never been hurt by gas prices (they just need to recycle free vegetable oil), they just flip the gas stations and hybrids the bird. We plan on a Expedition diesel and are going to convert it. Only down-sides are you need a place to get the oil (diner, fast food place etc) and they can't run in cold weather.