I have a 2001 Jetta Tdi , with the help of this web site and a scan gauge, I average 60 mpg.
My new car is a 1973 914 Porsche. I'm currently building a megasquirt EFI system for it, this will give me complete control of the timing and A/F ratio.
From searching the web, I can see the little 914 averaged about 35mpg highway back in the day. ( First EPA rating came out in 1976, last year of 914 production, but I'm unable to find them)
Although the 914 was factory EFI, it was very primitive when compared to what new EFI system can do. I hoping with some hypermiling the 914 will get high 60's....
Well, thanks to all the regular posters, and I'll post more when I have something to add.