Barring dragging brakes, those tires (what pressures btw), and maybe crappy gas?? Engine air filter I doubt very much: computer control adjusts for reduced air flow with partially clogged filter (which apparently is not your case) and might even IMPROVE mpg. It might be the hybrid battery, slowly going off. Oh, check the 12 volt condition? Have a look at the plugs? EGR circuit clogging, ditto for intake manifold, consider an oil catch can. Cabin air filter condition? C'mon, lol.
Are there no PC members in the vicinity who might offer to drive the car for a test (or ride along and observe/coach) to find out if it's just driving technique?
Sounds exactly like how I drive, especially the hard acceleration from a stop. Except I stay in PWR mode.
