When I first picked up my LC, I was getting 20.8 - 21mpgAs am I! I am an old timer and drive close to the speed limit here in Washington. I never have gotten better than 23.4 on premium or regular, doesn’t seem to make much difference. Thank you for giving me some hope!
After changing out the tires, I have been steady at 20.2 MPG for 3 months now, it never changes.
I am in flat as a pancake Florida, with average temps in 70s (this time of year) I drove at or close to the speed limit (depending on the road, 60, 65 or 70mph) and I use Costco Premium because around my neck of the woods, sand in gas station tanks is a real thing.
Costco does such volume and I have watched them maintain their pumps including changing out the pumps filters, so I know the gas is clean, plus Costco Premium is close to the price that regular gas stations are charging for Regular.