I get the same mileage (about 12.5 to 14 mpg). I run the same (size) tires, and have similar work on the vehicle. I dunno what's going on either, the milage issue is really irritating. I did the PCV thing a few tanks ago, and that seems to have helped a bit. Next I'll clean the EGR (49k miles) and switch over to 0W-30 Mobile 1 (dealer rec'd) and see if that helps.