Sorta via Neil Stevens (I read xkcd religiously myself):
…Yeah. My favorite crazy phenomenon was the 100 mpg carburetor/cars that ran on water/’gas pill’ that the auto/oil companies supposedly suppressed, back in the day. ‘Back in the day’ being the 1970s, when the US Army would have paid any sum that you might have wanted for a truck with four to five times the range of the ones that they were using.
Note, I did not say ‘tank.’ I said ‘truck.’
*I forget who said that first.