What is your mileage? 99 and ? S80-T6

[dcarlson12]

99 S80 T6
I drive about 80% highway and my mileage, as calculated my the onboard 'computer' displays average mileage as about 22.7 usgpm. When slightly 'heavy foot', displays 22.5. I have on occasion achieved 23.0
When driving speed limit of 100 km/hr (approx 62 mpm), instantaneous mileage will displays as approx. 30 usgpm when on level ground with steady foot.
What are others getting?

I bought the car when it had about 98000 miles on it and have never changed any O2 sensors. Wondering if changing the upstream sensor(s) would increase mileage. ??????

Edit Jan22: Forgot to say that the vehicle has about 133,000 miles on the odometer

[D_V_ENT850R]

Most likely not if the sensor gets slower to respond it will actually throw a slow response code. So no need to change it now! Do a stage 0, tune up, PCV, fuel filter, and vacuum lines if needed! My old 850R w 164,000 miles on it reads 22.1 avg mpg per tank. About 35mpg at steady cruise on flat roads @ 55mph! I filled up drove not so gently to the dragway, made 6-7 runs and drove home the same way I drove to the track and 18mpg was showing! So depends how you drive!