I bought a used 4X4 with 8000 miles & was wondering if anyone else has one. My truck gets about 13 miles per gallon I need to get better gas mileage. I added dual exhaust & I'm gonna add a KN air filter. What else could I do ? Mines a 2008 Quad cab. I think I bought a racing truck. I was driving a 2000 Toyota Tacoma V-6 3.9 liter.