2020 RX450h fill up at 7,183 miles 7/8/22 8:03pm. Traveled 444 miles, 10% city, short trips mostly 14 miles each way, 90% highway weather mostly 90F to 95F.
31.0 mpg calculated. The RX said 30.2 mpg. Filled up with QT Premium.

 

2020 RX450h fill up at 7,425 miles 7/16/22 1:39pm. Traveled 242.5 miles, 20% city, short trips mostly 14 miles each way, 80% highway weather mostly 90F to 95F.
31.7 mpg calculated. The RX said 30.1 mpg. Filled up with Sam's Club Premium.

2020 RX450h fill up at 7,782 miles 7/19/22 12:46pm. Traveled 356 miles, 0% city, 100% highway, weather mostly 90F to 95F. Highway speed 70 to 74 mph. The RX mpg did not like the higher speed.
26.6 mpg calculated. The RX said 27.3 mpg. Filled up with WAWA 93 Premium.

 

just wondering what are you getting for mpg? I’ve had the rx 450 HL for a few weeks and struggling to get the promised 30mpg while my friends driving the new 22 highlander are hitting over 40mpg. Thanks

 

22 highlander should be comparable to 23 RX 350h. 22 RX 45h is compatible with 2019 highlander hybrid.

 

With very careful and deliberate combined local and freeway driving I’ve hit 29 a few times but I think if I did a sustained long freeway drive I could hit 30-31.

 

My dash is reading 31 right now, so hand calculation is probably closer to 30. Not really doing anything special to achieve that mileage. You cannot drive these like you might with a Prius with a lot of “pulse and glide”. They are just too heavy. [EDIT: I should point out that you can still improve mileage slightly somewhat with pulse and glide techniques, just not to nearly the extent as you can with lighter vehicles, especially one like the Prius that is "purpose built" for high fuel economy. I didn't mean to suggest you can't still use driving techniques to maximize fuel economy in this heavier vehicle.]

We test drove the Highlander a couple of times before we settled on the RX. It is a completely different animal, running on a new platform with a 4 cylinder. It doesn’t have as much power as the RX and you really have to get on it to move it in some situations. It gets noisy when you are really putting your foot into it. We test drive on an interstate on-ramp near our dealer, and that on-ramp is a pretty steep climb. The RXh took it much more quietly and easily, but surely slurping up more gas at the same time. Take a test drive in a Highlander and you will see why the current versions really aren’t a good comparison.

 

2020 RX450h fill up at 8,205 miles 7/25/22. Traveled 425 miles, 100% highway at 70-74 mph, weather mostly 90F to 95F.
29.0 mpg calculated. The RX said 28.6 mpg. Filled up with QT Premium.

 

2020 RX450h fill up at 8,628 miles 8/8/22. Traveled 421.5 miles, 70% city short trips mostly 14 miles each way, 30% highway, weather mostly 90F to 95F.
30.9 mpg calculated. The RX said 30.5 mpg. Filled up with Sam's Club Premium 93 Octane.

 

When I refuel, I always remove the fuel nozzle when the pump "clicks off" - presumably indicating that the gas tank is full.

However, I have noticed quite a bit of variability in exactly how full the tank is after refueling depending on the place and gas pump where I pump gas.

For example, I refueled today after a trip that was about 90% highway miles. The onboard computer (center stack) showed I was averaging about 37.7 miles per gallon; however, when the pump clicked off, my self-computed MPG was 42.2! This has happened many times. In other refuels, the self-computed MPG has been lower than the onboard computer was showing. I'm guessing the variability in the "click off" from gas pump to gas pump may be as much as half a gallon to a gallon.

In the long run, it all averages out. But, it does create some weird MPG figures from refuel to refuel.

 

When I fill up I set the trigger to the slowest speed/flow and after the 1st click off I give it one more easy squeeze to the next click off. This does not overfill it and, I believe, helps accuracy. Just my way of doing it, as they say, your mileage may vary.

 

No wonder your mpg is nothing like everyone else’s!

 

When the pump shuts off should have no bearing on your calculation. As you should be reading the amount of gas pumped vs miles travelled since last refuel.

 

I always assumed the same thing, but is the original poster implying that the computer is 'assuming' the tank is full when it really isn't? Is the MPG computing system measuring exactly how many gallons are in the tank? I know that it will indicate that it's on empty when there's actually 2 to 3 gallons remaining.

 

My best estimate is that the onboard computer calculates range remaining (miles to empty) assuming about 15 gallons of fuel when "full." Since the 450h tank holds 17.4 gallons, that gives the driver a little more than a two gallon cushion when miles to empty registers zero.

 

I Bought a New Hybrid RX450HL 2022, it advertised 29MPG . Since I bought it, I am only getting 20.05 MP. I mostly drive side Street not a lot of Highway. I am not sure why Lexus Advertise 29 and only getting 20s.