I just filled up my new truck for the 2nd time and got my mpg results----20.5. I was pleased with the mileage-considering I have the 4.0 V6 w/MT, and do a mix of 50/50 highway, backroads. I am considering switching to synthetic oil on my next change, but I only have 23k on the truck now. Let me know when you guys think a good time to make the switch is and if it will help with the mpg.Thanks