My setup: 98 4.6 automatic, true dual magnaflows, intake, hypertech, 4.56 gears,9 inches of lift and 35" tires. I know im gonna have bad miles to the gallon but isnt 11 - 13 a little bit low? If this is right about where it should be, is there anything i can do to better my MPG? Other than taking off the lift and smaller tires.

 

Considering that you have the pre PI heads with less power, your engine is working a little harder. That sounds pretty good to me. My 01 4x4 supercab 5.4L auto with 3.55 gears and 17" wheels with 31" tall tires gets about 14mpg.
Has your speedo been corrected for the gears and tires?

 

Yes it is corrected with the superlift calibrator. Its not perfect yet but its only about 6 above what it says on the speedo. Its hard to get in contact with superlift with my work schedule to get some tweaking instructions. Also would maybe changing the pcv and fuel filter help any?

 

It may help a little. I really wouldn't expect much more mileage than you are getting now though. A good tune-up wouldn't hurt either, plugs wires etc. I recommend Motorcraft replacment parts for the best performance.