Under a new rule, the EPA will require you to buy a minimum of four gallons of gas from any pump that sells E15, or gasoline that's 15% ethanol
Ethanol is the controversial fuel additive made mostly from corn.
Most stations sell E10, or 10% ethanol. But the handful of stations that sell E15, which made its debut two months ago, generally dispense it from the same pump as E10. Problem is, anyone who fills up with E10 after an E15 buyer could get as much as a quart of residual E15, American Motorcyclist Association spokesman Peter Terhorst told the Milwaukee Journal Sentinel.
It's no big deal if you buy a lot of gas. But those who purchase just a few gallons from motorcyclists to folks with lawn mowers could damage their engines and void their warranties. Hence the 4-gallon rule.
The EPA's rule should help mitigate this, to be sure, and most critics contend that the rule reflects bad gas in the first place. The EPA certified vehicles back to the 2001 model year for the 15% ethanol blend, but automakers have demurred. The Auto Alliance, a trade association that represents 11 major automakers, raised concerns last May about potential engine failures. “Automakers did not build these vehicles to handle the more corrosive E15 fuel,” Alliance President Mitch Bainwol said in a statement.