Believe it or not I have been consistently getting 16mpg since I put my K&N in... even doing 90 mph..

1991 F150 Nite, 5.8L, E4OD, K&N filter charger... 160 K and still going strong
"That ol' Fords sure fast on the draw / out gun the Chevys and out runs the law" - Brooks and Dunn