As I thought: They don't perform a real-life test. I don't know anybody that would drive 48.3 mph on the hihghway where even modest speeds are 55. Consumer Reports does real-world tests, but I haven't looked at them lately.
Today I topped off with 87 octane gas and did a 39.1-mile trip at a steady 70 MPH with cruise control on, and in Normal Mode, mostly on the Interstate. My average MPG was 20.9 which is the highest MPG I've gotten with this truck in the month I've owned it. My 2020 SR5 with a V-6 got better gas...
I noticed the speedometers on the 2 Tacos, a 2020 and now a 2025, I've owned read 2 MPH lower than what my GPS says starting at about 65 MPH. Both had/have stock tires. This will have a marginal effect on the odometer reading, thus affecting mileage calculations.
I've always checked my gas mileage as it can be used as a gauge of something going wrong with the engine such as spark plugs or air filter needing changing.
I think EPA estimates are done at an unrealistic 55MPH, and I suspect on a dymo or windless conditions. This is my suspicion and I haven't researched how they do their estimates.
Today I installed EKR front and rear seat covers in my Taco OR. I watched a few videos before I started doing this, and I must say it looked much easier in the videos than in MY reality. I say this because the guys in the videos are younger than I, and they probably weren't fighting hand cramps...
I had a 2018 RAV4 that had the sunroof drains get clogged and the overflow ran into the passenger side A-pillar. RAVs had other drain problems, too. Design flaws that they know about and don't care to correct. I'll be sure to periodically check mine on the new truck, also.