The key points from the API report are below:
The additional E15 testing, completed this month, has identified an elevated incidence of fuel pump failures, fuel system component swelling, and impairment of fuel measurement systems in some of the vehicles tested. E15 could cause erratic and misleading fuel gauge readings or cause faulty check engine light illuminations. It also could cause critical components to break and stop fuel flow to the engine. Failure of these components could result in breakdowns that leave consumers stranded on busy roads and highways. Fuel system component problems did not develop in the CRC tests when either E10 or E0 was used. It is difficult to precisely calculate how many vehicles E15 could harm. That depends on how widely it is used and other factors. But, given the kinds of vehicles tested, it is safe to say that millions could be impacted.
In 2010 and 2011, EPA gave the green light to use E15 - the 15 percent ethanol gasoline blend - in model-year-2001-and-later cars and some other vehicles. EPA's action was irresponsible. EPA knew E15 vehicle testing was ongoing but decided not to wait for the results. Why did EPA move forward prematurely? Part of the answer may be the need to raise the permissible concentration level of ethanol so that greater volumes could be used, as required by the federal Renewable Fuel Standard. Most gasoline sold today is an E10 blend, but rising volume requirements under the law can't be met much longer without going to higher blends. When Congress passed the law, it could not know it was creating this problem. Today we know. The answer is to repeal the RFS before it puts millions of vehicles and many motorists at risk.