High rpm, poor mpg

[fortjp500]

Hi everyone, I have a 2015 Yaris hatchback base with about 58k on it. I've had it for over a year and the most recent full gas tank averaged about 20.5mpg (I always fill the tank full and reset my trip A odometer to calculate). I don't ever remember it being this bad a year ago. It was maybe 30mpg then, with little changing in driving style between then and now.

My wife reports that when starting from a complete stop that barely touching the pedal will result in what feels like "flooring it" with the rpms shooting up to shift out of first gear. I'm thinking this is the reason for the bad mpg. But resetting the computer didn't do it and the Yaris doesn't seem to be learning and getting any better.

I checked engine compression and it was 170psi with little variation between cylinders. The spark plugs did not show any evidence of fouling. Long term fuel trim is -10%. I replaced the downstream O2 sensor about 6 months ago with a Denso to fix a separate CEL and that fixed the issue back then. No CEL now. The engine air filter looks clean, and I cleaned the MAF sensor about a year ago. The rear brakes are definitely not dragging. The fronts' friction seem normal resistance considering the drivetrain attached. The alignment is spot on, and the tire pressure is right.

Has anyone had something similar?