Man, I want one of these 30 mpg diesels!
The two gallon 50 mpg figure is a most likely a statistical fluke.
Been there done that.
The car mags average out fuel consumption over a full year.
I started keeping an Excel spreadsheet tracking my fuel purchases and was averaging just over 20 mpg.
I haven't kept up with my data entry, having just bought a house, and trying to sell my old house. Maybe after I have some $$$ I might try to tune up the old SD, or get a newer car of some type, maybe a TD wagon.

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic