Possibly the Catylatic Converter.
fuel pressure regulator
You cannot do anything to dramatically decrease your gas mileage. However, if you practice good driving habits like gentle stops and starts and gradual acceleration, you can conserve gas.
The EPA mileage estimate for the 2001 Ford Mustang is 17 mpg in the city, 26 mpg on the highway.
The EPA mileage estimate for the 2002 Ford Mustang is 17 mpg in the city, 27 mpg on the highway.
The EPA mileage estimate for the 2012 Ford Mustang is 19 mpg in the city, 29 mpg on the highway.
The EPA mileage estimate for the 2011 Ford Mustang is 19 mpg in the city, 29 mpg on the highway.
The EPA mileage estimate for the 2004 Ford Mustang is 18 mpg in the city, 27 mpg on the highway.
The EPA mileage estimate for the 2014 Ford Mustang is 19 mpg in the city, 29 mpg on the highway.
The EPA mileage estimate for the 2005 Ford Mustang is 17 mpg in the city, 26 mpg on the highway.
The EPA mileage estimate for the 2007 Ford Mustang is 17 mpg in the city, 25 mpg on the highway.
The EPA mileage estimate for the 2010 Ford Mustang is 18 mpg in the city, 26 mpg on the highway.
The EPA mileage estimate for the 2008 Ford Mustang is 17 mpg in the city, 26 mpg on the highway.
The EPA mileage estimate for the 2006 Ford Mustang is 17 mpg in the city, 26 mpg on the highway.