You've got the best cai from the factory. Install a k&n and call it done. I'm running a k&n rf1012 warm air setup and getting 20 mpg. Search the forum for "just gained 8mpg and you'll find a world of info.
1995 SWB 300 I6, M5OD, 273 gears, 235/75r15's, 21MPG, 50" Led Light Bar, 6" Off Road Lights, Full Synthetic Fluids, K&N RF1012
"Gentlemen, we can rebuild them. We have the technology. We have the capability to build the world's first unstoppable truck. The F-150 will be that truck. Better than it was before. Better, stronger, faster."