Magnets
Magnets
They are junk...they are snake oil pure and simple.
http://www.ftc.gov/bcp/conline/pubs/autos/gasave.htm
Here's a quote...
Fuel Line Devices (magnets). These magnetic devices, clamped to the outside of the fuel line or installed in the fuel line, claim to change the molecular structure of gasoline.
The EPA has evaluated: PETRO-MIZER; POLARION-X; Super-Mag Fuel Extender; Wickliff Polarizer [fuel line magnet/intake air magnet].
Those with asterisks may save measurable, but small, amounts of gas. All others have been found not to increase fuel economy.
So, basically, it doesn't do anything but lighten your pocket, which very well might give better fuel economy...here's another quote from a site which tested them...
"So in the end, which gas saver saved the most?
The mileage actually got worse three percent on the truck with the Fuel Saver Pro magnet.
The Super Fuel Max magnet performed even worse, decreasing mileage by nearly five percent."
Bill Jenkins
92 Ty #1752