My research has shown that if you don't add bigger wheels and tires the gas mileage will stay about the same. Maybe at worst you might lose 1/2 of a mpg.
PRG products makes a good kit
The EPA mileage estimate for the 2005 Nissan Titan is 13 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2008 Nissan Titan is 12 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2014 Nissan Titan is 13 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2007 Nissan Titan is 12 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2010 Nissan Titan is 13 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2006 Nissan Titan is 13 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2011 Nissan Titan is 13 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2013 Nissan Titan is 13 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2009 Nissan Titan is 13 mpg in the city, 17 mpg on the highway.
The EPA mileage estimate for the 2012 Nissan Titan is 13 mpg in the city, 18 mpg on the highway.
The EPA mileage estimate for the 2004 Nissan Titan is 13 mpg in the city, 17 mpg on the highway.