its crap.
http://cgi.ebay.com/ebaymotors/ws/eB...tem=7939739480 , BTW...

"...In general, leaning out the fuel/oxygen ratio will cause a power loss, but fuel economy gain, conversely richening the mix will cause a slight (usually less than 1/2 mpg) reduction in fuel economy, but an increase in power..."

this statement is untrue... leaning out a mixture INCREASES power. obviously richening up the mixture will decrease gas mileage, but it does NOT increase power. increasing oxygen increases power.