[Frank Lee]

Originally Posted by Old Tele man

Not, when you consider these two points: (1) all EPA tests are performend using 'neat' Indolene 91 octane gasoline, NOT the ethanol-diluted E10 stuff everybody is forced to use; and (2) some manufacturers stipulate milage tests be performed with daytime running lamps (DRL) and automatic headlamps and other "normal" electrical loads disconnected (which can only be done by pulling fuses!). So, how often do you pull fuses before you drive to work?

Also, up to now, EPA has NOT had a standard E85 fuel specified, so they relied upon numbers provided from manufacturers tests. They, now, however, have proposed an E85 standard fuel...but, it's not (yet) been approved.

Measuring Fuel Use
For vehicles using carbon-based fuels (e.g., gasoline, diesel, natural gas, etc.), a hose is connected to the tailpipe to collect the engine exhaust during the tests.

The carbon in the exhaust is measured to calculate the amount of fuel burned during the test. This is more accurate than using a fuel gauge.

This method does not work for vehicles using non-carbon-based fuels, such as fuel cell vehicles and electric vehicles.

How Vehicles Are Tested

Accounts vary, but links here https://www.google.com/#bav=on.2,or....ends+are+there claim up to 59 different blends of gasoline sold in the U.S.:

http://www.gao.gov/products/GAO-05-421