I installed a Volant CAI on a 2005 Expedition 5.4L. Definately noticed a difference in the way my truck drives. Gas mileage went from 13.4 to 14.1 MPG. I have a friend with a 2002 Expedition 4.6L who is thinking about installing one. His motivation is improved gas mileage. Can you tell me what your mileage was before CAI and after?