The mileage is still not Good. See:
Everything above 40 mpg is around town, suburban, everything below 40 is on the highway, on a trip, 70 mph plus.
I have been using 50 psi for over a hundred thousand miles with no problems, and again if you are ever in the Atlanta Area we could try your car on my test loop to compare cars MPG's to see if their is a problem.
We could also put My ScanGaugeII on it to see what's going on.