take into consideration how long the engine idled while tech specialist assisted you with delivery. Then more idling at home while adjusting all the settings to your liking.
Based on my NX, mileage improved over time as engine breaks in.
Third week of RX, we have gone from 12 mpg to 18.
Based on the fuel comments, and my personal liking, we began using Premium last week. Since Lexus says minimum 87, I see nothing illogical about using Premium.
And Costco's premium price is lower than other's regular. Just need to get there when they open.

 

I get around 25 mpg for my commute on RX. While my Mitsubishi Outlander (compact 4-cyl SUV) can easily get 31 for the same route, 25 is not bad for RX.

But, any stop and go will kill RX's gas mileage. It will drop to 17 or 18, while Outlander will maintain 28 mpg on the similar situation. I guess V6 is thirsty on gas especially on idle.

 

The RX weighs significantly more than the Outlander. Weight has a lot of impact on fuel economy. Especially in stop and go conditions.

 

After two tanks with the summer tires, 1.5 mpg better mileage, of course it's much better weather and not as much idling. Still not as good as the 3RX. Getting 22 MPG was getting 24 with the 3RX...both mostly 90 % city driving

 

What? I get way less than that!!! I get around 18 MPG (13 L/100Km) and 95% city driving with a lot of stop signs though...

The result you have I what I do if I just filled up and hit the highway!

 

I usually get 22 mpg ( think we're both in Canadian gallons ) I was not impressed with 20-21 all winter. My 3RX got 22 at worst.

I drive in Normal mode at usually drive casually. Not too many hard starts and glide to stops. I don't hold up traffic and usually drive faster than 60% of other motorists. Lots of stop and go driving and when I am on the highway it's only for about 10 Kms.

On the Highway I get around 27 MPG. Went to Toronto a week ago and averaged 26.5. Almost all at 115-120 Kph...not too much wind either direction.

I thought with the 8 speed it would be better...24 city 30 highway. The old 3RX always got over 30 on the highway.

I still do MPG as I have for 40 years. Kilometers per litre or litres per 100 kilometers is greek to me!

 

I don't know how one need to drive to get over 30 on the highway when I cannot get 30 in my Acura TL which is much more ergonomic aerodynamic.

Looking on fuelly website average for RX are more realistic:

2017 23.1
2016 20.4
2015 19.8
2014 19.7
2013 19.9


http://www.fuelly.com/car/lexus/rx350

 

I think you mean aerodynamic?

 

Up here in the cold north, our gallon is bigger so it probably looks crazy when us Canucks talk about MPG...sorry for the confusion.

 

Just a little conversion....23.1 is 27.7 for an imperial gallon....I should have stated I was talking Canadian gallons. I think a US gallon is 4 litres and ours is 5

 

I had no idea there was a difference. Had to look that up. Thank you for pointing out.

 

When I went on vacation in the NJ last summer and we had the RX 250 350 2016 for 3 months, I filled Premium in upper New-York state and I was getting 8.1L/100Km on the highway using cruise control. According to Online Conversion, it gives 29 MPG (US). That was the best I got from it so far.

 

That's about 35 MPG (Imp gallon or Canadian)... I have ever only got that on my 3RX and even then I thought I messed up somehow...too good to be accurate. Good to know that some days you could actually get that kind of mileage...weather and speed can really help or hinder these numbers.

 

i use power in my custom driving mode with my mostly city driving and the mpg is abysmal at about 13mpg city, anyone else getting these horrible numbers?

 

'16 RX 450
Purchased 7/1/16
4,280 miles (95% city driving)
MPG: 29.9 (per car gauge - have never reset it)

Notes:
All miles driven in "NORMAL" drive mode.
Tires contain nitrogen, set to 32 PSI for comfort.
Lead foot; love to sprint from stoplights.