[MetroMPG]

I tend to respect what Tony has to say at http://fuelsaving.info - and one of them was that fuel heating - to the point of total vaporisation - gave minimal results:

I have even tested a device that completely vaporizes the fuel on a heated surface*, eliminating fuel droplets altogether, and the economy improvement was tiny (1 - 2% at most).

http://www.fuelsaving.info/atomisation.htm