I want to tune my 6.4 to increase my mileage but not damage the truck. dont want the same problems I had with the 6.0. I was told intake and exhaust would improve mpg didnt happen. sct tuner and egr delete would help didnt help it just kept getting worse every time I would change something went from 19 mpg to 15 after every thing was done. dont need that crap again just tell me what really worked for you not what you read or heard.