This email has been floating around the Internet for years and makes a resurgence each time gas prices go up.
Almost all of these claims have been debunked or the gas savings is so minimal (less than 1/10 of a cent on a tank of gas) that it is basically worthless information.
When gas hit $4.00/gal a few years ago a local TV station did a piece on this with input from the University of Minnesota and debunked it. Some of the tips may have some validity in a refinery that pumps millions of gallons of fuel a day but not for the local consumer.
If you really want to save gas then: Make sure your car is tuned up and your tires are at the right pressure.