markneups

You can just forget the tire thing. That by itself is not going to run your mileage down such as you state above. The RX is notorious for bad mpg. My mpg dropped everyday from the time I bought it. The best I ever did was 17.4. That's just the way it is with these cars. Been that way since the day they introduced them. Back then it was even high test gas that HAD to be used. I could not endure the bad mpg any longer and as stated above-- picked up,the newRX450 h. Only have 400 miles on the clock but mpg as of today is 27.3 city only-- no highway. Goes up about a mile per day. I'm sure 30 plus is going to happen. Plus-- looked at the underside in the wheel well area and all kinds of extra insulation. The whole area is covered. Not like the regularRX that has only part covering. Hard to believe but the 450h is twice as quiet. I know--- hard to believ- but true. So bottom line is --- bite the bullet and get the 450h or just use the money you saved buying the rx350 for gasoline. Probably the better way to go--- but-- I just could not adjust to that horrible mpg.Thats me-- but I just love that hybrid. Plan on owning for years to come. Especially when gasoline goes back,to $4.00 per. And it will.

lexus114

thats odd because im getting 18.0 right now. mostly rural/city driving

JV6

My best was 13.7L so roughly 17mpg, 75% city. 2014 RX350

JDR76

I'm getting about 21 mpg average, with what I would call "urban" use on my RX. Get around 25 on highway trips, and around 18 in the city. Very happy with the mileage in my 350.

Can you take a picture? I'm not sure what you're referring to, as the wheel wells in my 350 are definitely fully insulated by all outward appearances.

davrober

This is interesting, my milage has gone up a bit since it warmed up . we are around 45 degrees now and the milage is up around 16 . Thats a big increase from 13-14. I guess there must be something to the idea that winter gas in the NE is different based on the season. Im hoping I get back to 17.5 , Im no t in the city but eastern LI . It is AWD so that would hurt it a bit but 13 ? well its getting better.. Im always gassing at Sunoco here because they are the only guys with 91 octain. The rest go from 89 to 93 .

jfelbab

My latest trip, Milwaukee, WI to Cape Coral, FL and back.

This trip included some horrendous traffic delays around Tampa, Atlanta and Nashville due to road construction and accidents, still the 2014 RX350 acquitted itself quite nicely. The RX was loaded with around 700 pounds of people and luggage. I used Shell 87 octane for most of the trip.

2776 miles, 112.4 gallons = 24.7 MPG

The only thing I really disliked was my tires. The road noise on I-75 in Georgia and much of I-57 in Illinois was annoying beyond belief. I have the OEM 19" Dunlop Grandtrek Touring tires and I consider them about the worst tire I've ever driven on. Besides the noise, they lack any traction in snow and wintery conditions and in wet driving conditions. I'm not going through another winter with them. I consider them unsafe in those conditions.

DGB67

Just bought a pre-owned 2013 RX.
After the first tank of gas, I averaged 21.5 MPG.
Using I assume 87 octane that the dealer filled my tank with.
I do mostly highway driving.
My second tank of gas, I switched to 89 octane.
I'll report the results when I need to re-fill again.

markneups

Not sure how to do the picture thing. The only insulation in the rear wheel well on the 2013 RX350 I traded in was just behind the wheel about a foot and a half long piece---but no where else in the rear. The front on the 450h is the same as the rx350. The rear on the rx450h is fully insulated all around the wheel well front,top and back. Big difference.

erom43

I started posting on this thread back in 2013, when my new RX350 had just a few thousand miles on it. Back then I would get anywhere from 22.0 to 24.5 mpg on interstate driving, and wondered why the inconsistency. Now with over 30K on the car, that same driving is getting a consistent 23.5 to 24.5 mpg. Not sure if it's engine break in, OEM tires, or what.

BTW, I still see some posts citing mileages for local driving for comparison purposes. There are just too many variables to be able to compare accurately. In my own car, mileage can vary from 16.5 mpg to 19.5 mpg when around town only. I even notice a difference between drivers in our family. My highway mileage stats were from interstate trips, doing 70-80 mph for over 500 miles, and did not include any local driving.

JDR76

That's very strange. I can't really understand why that is. On my '13 RX350, the entire rear wheel well has insulation - front, top, and rear.

markneups

The only thing I could figure out is the snow and frozen slush clings to the insulation. Causing a terrible build up under the wheel well. Could not get it off because it would cling like iron. Not even at the car wash would it come off. I tried to pry it loose on a few occasions but you could see that you would be pulling off the insulation if you went to far. But-- that would not explain why the 450 h would have the full insulation under the wheel well and not the 350.

JDR76

I'm more mystified as to why your 350 would not have the insulation but mine does. Anyway, we're off topic of fuel mileage. We can start another thread if we want to discuss this further. Have a great day!

JDR76

Just got back from a 400 mile round trip in the RX. Car was loaded up with the fam, stuffed to the brim, with my Thule cargo box attached to the roof. Trip was all highway, with the vast majority of it being around 75-80 mph. Weather was cool, with lots of wind and heavy rains. Traffic was light. I used the radar cruise control less than half of the time.

My round trip averaged 21.8 mpg. I find the cargo box takes a hit of about 2 mpg.

I'm very pleased, as always, with my RX. Great fuel mileage, lots of room, and that fantastic effortless cruising I love about the RX.

rparian636

Easy formula, I got my wife out from behind the wheel. I had a leg injury and she was doing all the driving for the last few months. She is an aggressive driver and has no sense of fuel economy.
I observed her with the foot on the accelerator right to the stop. Never a coasting, like getting off the ramp on the highway for our exit; it is downhill to a stop sign and she accelerates to the last 50 ft.
Once I started driving, the same route, back and forth to physical therapy, groceries, etc, my MPG went from her 16.0 to a my sweet 21.9. Goes to the theory that the factors to consider amongst tire pressure, wind and weight is driving style. I'm just saying'.

lexus114

im back up to 19mpg`s again!