Just filled up for the first time in my '23 Hybrid XL. I picked it up from the dealer with a full tank of gas.
I put in 14.2 gallons and had 644.2 miles on the trip meter for an average of 45.37 mpg!
I was only getting about 17.5 mpg with my '02 highlander, so this is a huge upgrade!
@st3v I have a '23 xl hybrid and I also noticed the high frequency noise only with the engine running, but for me it's between 20 and 30 mph. The sound is not there on battery only, and it's only in the 20-30mph speed range. It's only noticeable when the radio is off and there isn't much road noise.