It's been awhile, but long story short, after purchasing tuning and running the living H*ll out of the truck, the injectors started to go. being a broke college kid, I didnt get to fixing it until earlier this week.
I had been getting 18's and 19's, and even had one pair of tanks break the 20 mark... then the injectors started going downhill...
Stock AB's at 279K miles, with tuning, and I was lucky to average more than 7 or 8 mpg
Recently I replaced those with a nice set of low mileage AD's in great shape.
and I learned something-
when your injectors are going out and you're trying to make them live, you learn how to drive very very very lightly.
First two tanks from the new injectors? 22.1 mpg
at about 75% hwy, 25% backroads/city/traffic.
I guess what i'm saying is, if you can, replace your injectors as soon as they start to go... but if not, enjoy the relearning process...