I am very skeptical of this. I can't say it's total BS yet, since I haven't done the research, but it very definitely sounds too good to be true.
One thing in particular keeps bothering me. They mention "research back in the '50s" as supporting this, so why is it only coming up now? By my count, there's been at least 45 years in which this could have been publicized, so why are we only hearing about it now?
The source for the linked article starts off by talking about how the "American Car Manufacturers . . . . want bad mileage." This ought to be a warning all its own: why would the Big Three have wasted so much R&D money on improving gas mileage to meet CAFE standards, when they could just have lobbied to get acetone into the gasoline instead?
The author claims that acetone works due to its "rapid inherent molecular vibration that prevents fuel from escaping the combustion process and going through unburned." The implication is that the acetone shakes loose the gasoline molecules, causing better vaporization and thus better mileage. I'm not a chemical engineer, but that sounds like a bogus explanation to me. Even assuming that acetone has a rapid inherent molecular vibration, I don't see how that would affect the bonds between the molecules of gasoline--especially given the low concentration of acetone that is supposed to be necessary to make this work.
There's more circumstantial evidence that this is not altogether on-the-level. The continuous ranting against the Big Oil Conspiracy is one piece. Another is the repeated plugging of the ScanGauge, which appears to be some sort of a mileage indicator. Neither of these are hallmarks of good scientific writing.
Finally, without meaning to pass judgement on the motivations of this inventor, this looks suspiciously like a variant on the old story of the miracle carburetor (see snopes.com
for details and a nice debunking). The general theory--that gasoline doesn't vaporize completely in an unmodified engine--is also the basis for hundreds of questionable devices that have come and gone over the years. This might work, but I would really, really like to see a scientific test of it under controlled conditions before I start putting acetone in my gas.