My 2016 Avalon Hybrid Limited averaged 32-35 mpg since I bought it. I kept taking it to the dealership complaining about poor fuel economy (my 2013 Avalon Hybrid Limited got 40 mpg always) but Toyota kept telling me there was nothing wrong with it. If I put the car in the Sport Mode rather than the ECO mode, I got substantially BETTER fuel economy! Not the expected result! The dealer even sent data to Toyota engineers with the same result, nothing wrong! Finally, after 2 years, I asked them to reset the computer that runs the hybrid synergy system. They did it and now I am getting 42 mpg in the ECO mode. Same car!
I regret to report that the improvement in fuel economy was short lived. Within 5 days, my 2016 Toyota Avalon Hybrid Limited went back to 32 mpg (CITY) in the ECO mode. Sport mode is still achieving about 39 to 40 mpg (CITY). I am back contacting the dealership.
HERE IS A PHOTO OF THE AVERAGE FUEL ECONOMY SCREEN. I reset the computer last night (on my own) and drove a 5 mile roundtrip this morning. Back to 32-33 mpg (CITY) in the ECO mode.