well you don't drive my truck do you? i got a 6 mpg gain in the city and about 8 ish on hwy. I'm running around 24 now in the hwy and about 16 to 18 in city. The factory system had 2 different airflow diverters that slowed and lessoned the amount of air flowing in. infact with the factory system I gainded 2 mpg with just removing the air filter. even with a k&n.