Automakers and engine manufacturers are suing the Environmental Protection Agency over a plan to allow the sale of gasoline containing 15 percent ethanol.

The Obama administration ruled in October that gas stations could start selling the corn-based ethanol blend for vehicles built since the 2007 model year. It's an increase from the current blend of 10 percent ethanol.

Automakers say they are worried the EPA decision would eventually lead to motorists unknowingly filling up their older cars and trucks with E15 and hurting their engines. The problem could be exacerbated if E15 fuels are cheaper than more conventional blends, prompting owners of older vehicles to use the fuel despite the potential engine problems.