Our salesman confided in us that the dealer puts regular in their loaners.
Ray

 

We run regular in our 11. Once I put premium into the tank and an espresso machine came out of the dash and made me a latte. : )
Seriously, one tank of premium gave us +1 MPG and not much else.
If running regular would muck up the engine, there probably would be an escape clause from the legal beagles in the terms of the warranty.
The days of a carburetor gumming up from varnish in the gas are over.
I think the premium recommendation is to keep people away from the new 15% ethanol gas.
Hope this helps.
Ray

 

Well it's been two years since I made the original post and I've been using the regular ever since. Saved a boatload of money and never had any problems.

 

Excellent! I read through this thread earlier today and wondered what the OP decided to do. Good for you BatmobileX for making the decision that best fits your needs. My wife runs 87 octane in her 2010 RX350 with absolutely no issues. I run premium in my SC because I drive it much harder than she will ever drive the RX. If I drove the RX as often and as hard as I drive the SC, I'd probably run premium in it too. I've ran premium in the RX in the past and can't tell any difference under normal driving conditions.

 

Thanks for updating us. Here in Ontario (Canada), the price difference between 87 and 93 octance is 0.68cents a gallon. So, yes, it's almost 20% in savings.

 

Haha .. Dealers have to save to survive.

 

I know! Right?
Then they sell these loaners as CPO.
And the poor buyer will gas up using premium ( after the RX has been drinking regular for the paat 1-2 years)

 

Read the manual and put whatever the manufacturer recommended! You are wasting your money otherwise (to pump Premium when not required). Brand of gas is more important.

 

The 2010, 2011, 2012, 2013, 2014 engine is the same as in the Highlander and for the Highlander all those years the manual says regular. Lexus put the premium in the manual to make the owners feel special, but after the economic crisis hit in mid 2012 they changed the wording to "Regular" in order no to scare the now poor RX buyers.

 

I use 87 octane in my 2010 RX and the previous owners used 93 exclusively. The owners are my parents so I know it was filled with 93.

I unplugged the battery to install a Remote Starter and afterwards the engine is more responsive with the 87. I assume the engine ECU remapped to the fuel after the battery was disconnected.

I have great throttle response with 87 and get 20-22 mpg mostly suburban driving.

 

I purchased my 2010 RX 350 3/12 years ago from a dealer coming off a lease with 28k miles. Since then I have used on 87 octane and experiment once or twice with higher octane premium gas and found no difference in mpg or performance. The vehicle now has 99,000 miles and still purrs like a kitten.
I agree with the post that said that Lexus wanted owners to "feel" premium and special. I have found that my dealer services mostly sociopaths that like spending $90 for an oil change and $75 for a tire rotation in order to get a $10 car wash. I think is makes them feel special. I bring my Lexus to a GM dealer and get synthetic oil and tire rotation and a "lexus" type car wash for $59.99. The service manager told me that the engine in the Lexus would run the same without premium. He used to be an Exxon regional manager and educated me a lot about "premium" fuel. No surprise, but it is the oil companies that push premium as it has their higher profit margins. He said it was actually more important to run clean gas and use stations that change their filter frequently. All name brand fuels, like Exxon, Shell, Sunoco etc. do that.. Be wary of brand X fuel, as some will change the filters often but many do not.

Back to MPG and 87 octane. I squeak out 24.5 highway and 18 mpg city with an overall average of 22.5 mpg. I am happy with this for a smooth running 6 cylinder that can get out into highway traffic with ease.

 

Same here, I have been using 87 octane in both of my vehicles 2010 RX350 & 2007 ES350 for many years .. no issues to report.

 

I thought I had updated this thread but I guess not. A few months ago I went in for a routine maintenance and the mechanic took me aside, asked what kind of crap gas I've been using. I said Costco 87 octane. He told me that was a bad idea and it was messing with the engine. He said I needed to run 3 full tanks worth of Mobil, Shell, or BP premium and then I could "play with it a little." So now this is what I do. If I'm using cheap gas such as Costco, Valero, Marathon, or some no-name brand, I use the premium. I avoid those brands as much as possible but in a pinch I just make sure it's premium. If I go to Mobil, Shell, or BP, it's non-premium. This is a compromise that doesn't deplete my wallet. I do a lot of highway driving, but I'm averaging 25 mpg currently.

 

Your mechanic doesn't know squat about gas.Costco and Valero are both top tier gas.
That stated I use Shell 93 about 95% of the time for my 5K miles per..

http://www.toptiergas.com/retailers/

 

I use 91+ octane