OK, folks . . I have a 2005 4x4 quad cab 48re with a 4. 10 re. I know, I have perhaps the worst setup for fuel economy, but it seems to be falling instead of increaseing. I drove a 200 mile trip when the truck had 1500 miles on it, and I was around 17. 8, now, same trip I am at 15. 4. I am using...