Oldfart

If you let car idling for an hour you will get 0MPG in order to get at least some MPG car need to be moving and to get the most MPG car need to get into final gear in most cases speed must be over 45MPH before transmission will shift in final gear but driving at the edge of shift point will keep torque converter unlocked in order to reduce stress on engine. Of course it all depends on aerodynamic drag and weight of passengers and cargo. Exactly why hybrid cars get better MPG by shutting off gas powered engine at idle.

Another way of looking at this:

At idle engine makes 700 RPM just to keep all systems running smooth and getting 0MPG at the same time.

On freeway at 65 MPH engine runs at about 2200RPM therefore making about 2030 revolutions per mile. In city driving engine goes from 700RPMs at idle to series of run ups to 3000 to 4500 and dropping to 2000 as it shifts through gears (depending on driving style). Lets for fun assume that on average at 20MPH average city RPM is same 2200RPM = 6600 revolutions per mile. Basically in city driving engine makes 3 times more revolutions per mile. So with less revolutions per mile one gets better MPG. Another reason why comparing MPG for city driving is useless because it greatly depends on commute (number of stop signs, lights, city speed limits).

jfelbab

My last road trip, 2,080 miles, 76 gallons of gas = 26.7 Avg. MPG. This was in my 2014 RX330 AWD, loaded with about 900 pounds of people, computers and luggage. Route was 90-95% highway with cruise mostly set at 75 using 87 octane E10 gas. This trip was mostly on flatland in hot 91-98° weather with AC on all the way.

garbo

230 mile trip with 2 people and 4 pieces of luggage. Highway driving at 65-70 mph got 26.4 mpg using super. Car has 600 miles.

erom43

You make good points, but when I refer to idle power, it is with the car in gear and moving....not in park or neutral. You make a good point that there is likely a sweet spot, based on weight, fuel flow, speed and gear ratios. However, my point is that the sweet spot is more likely to be at minimum power, and very low speed, rather than anything above 50 mph. I have no idea what that speed would be, but if I remember by physics correctly, drag is proportional to the square of the velocity. That would mean slower speeds yield higher MPG.

coachlkg

I think you have a 2014 RX350 AWD. Anyway my 2013 RX350 AWD currently gets 23.7 under similar conditions.

gsteitz

First tank of gas on my new to me 2013, getting 19 mpg with mixed driving. Very pleased as I was averaging 21 mpg on my 2006 GS 300 and this feels significantly heavier.

snowman22

I had a new 2013 AWD. Mileage topped out at 16.5 under all driving conditions. I guess I would have been happy at 19. But--- mpg,should be better than 19. I finally got fed up and traded in a year early for the new 450h. Then again since I bought the hybrid gasoline has fallen and still has farther to go. But-- I'm still a happy camper at 30 mpg. Just saving mores on gasoline than before. Good luck-- I hope,your mpg gets better--- or--- gasoline goes to $2.00 per.

JDR76

Just completed another Seattle/Portland round trip, 205 miles each way.

On the way there, light traffic, average about 75 mph, a very wonderful 26.1 mpg.

On the way back, atrocious stop and go traffic conditions, adding 45 minutes to the drive. 22.3 mpg.

Love my RX!

RXRunner

We just completed our vacation trip from eastern Iowa to Delaware. We had a mix of interstate and 2-lane roads both out and back. Plenty of power in the mountains of WV and PA. Speeds 55 to 75 depending on the traffic. We covered 2,314.3 miles and used 96.477 gallons of 87 octane gas. We ended up with an average of 23.984 mpg. I never purchased any Premium gas. It was fairly hit and miss to find it. We were very pleased with the mileage for the trip. I also calculated various individual tanks and it ranged from a low of 21.5 mpg to a high of 25.4 mpg. With the great ride and all the Lexus creature comforts it was a great trip.

PLamarine

2010 RX350...got it last week from my mother (she traded for a smaller SUV). Only had 21,000 miles on it.

Been getting about 21-22 mpg city and the computer readout has been very accurate. No real need to check gallons and miles.

jimkca

My RX350 AWD has just over 6000 miles on it. Driving mostly in speeds of 40-50 mph. Averaging 20 mpg. Little disappointed.

lexus114

disappointed? why? thats good mpg`s

ericsan13

Washington driver here, mostly on the eastside. I'm averaging 17-18mpg now - I would be happy to get 20.

FWIW Costco 87 octane, 6 mile one-way commute.

JDR76

Washingtonians unite!

In the north end here (Everett/Mukilteo). My wife drives the RX daily. She has a 12 mile each way commute to Edmonds, pretty much all on the Mukilteo Speedway and Hwy 99, so lots of traffic lights. She is averaging 20, which I think is good given that commute. We get around 24-26 on long trips.

coachlkg

Drove from Indy to Niagara Falls and back two weeks ago--averaged 22.3. The RX 350 is a very comfortable vehicle, but it does not get good gas mileage--city or highway.