wondering if i can get better mileage from my 6.0L. I was recomended to use the DiabloSport Predator and can switch to "economy" mode. This will give me three miles per gallon better or more. Has anybody used this or any similar device and does it really work. THis device sells for about $300. I do alot of highway driving not pulling a trailer so if this works it can pay for itself.
