During May our car hit a curb hard enough that both tires on the drivers side had to be replaced ( flat and a bubble). At the time, the technician tested the car for other damage and found none---- other than needing to be realigned - which he did. Since then, the gas mileage has declined and seems to be getting worse. Prior to the incident, we had been averaging about 53 mpg with better mileage in good weather and a little less in the heat of the summer. After the incident, the mileage seemed to drop to about 47-48 . Then in June the car was due for 20,000 mile service which was done and no problems found. Oil was changed and airfilters checked ( they had been replaced at 15,000 miles). Since the service, the mileage hasn't improved and seems to be getting a bit worse --last couple tanks down to about 45.5mpg. There has been no change to car weight, driver style, or avg driving profile. I've tried a couple different brands of gasoline, checked air pressure, fluid levels etc.. I've been running the air conditioner in the summer but last year I was getting at least 50-52mpg during the summer. It feels that the car is struggling more in lower gears and not up-shifting as easy. Is there a sensor that maybe got out of line or some other part that could be causing this issue that is not quickly noticable when the car is on the rack ????