thought this might interest you guy`s. this is what i got back from lexus corporate: honestly, i`m confused? read the bottom part first.



Thank you for allowing us to be of service to you.


Subject
fuel octane

Discussion Thread
Response Via Email (Aaron Gonzales) 08/10/2015 01:21 PM
Dear Mr. McArdle,


Thank you for contacting Lexus Customer Satisfaction. We are dedicated to providing superior service.

Per our owner's manual, Premium unleaded gasoline with an octane rating of 91 or higher is required for optimal engine and mileage performance. However, if such premium type cannot be obtained, you may use regular unleaded gasoline with an octane rating as low as 87.

If you require further assistance, please respond to this e-mail, or contact Lexus Customer Satisfaction at 1-800-255-3987, Monday through Friday, 5:00 am to 6:00 pm, or Saturday, 7:00 am to 4:00 pm, Pacific Time.


Sincerely,


Aaron Gonzales
Lexus Customer Satisfaction
Customer By Web Form (Ryan McArdle) 08/10/2015 12:57 PM
Hi, I bought a new 2015 RX 350 last may. I noticed the manual states to use 87 octane fuel or higher. Will the vehicle get better fuel millage and burn cleaner on premium or 89 octane fuel?

Thanks,
Ryan

 

If you're confused or require further assistance as the response suggests, why not call Lexus Customer Service and have a discussion with them? Asking this community of enthusiasts will just get a bunch of opinions like has been discussed for years.

IMHO, Aaron likely accidentally replied as if you had a RX450h, when you have a base RX350. While there are zillions of opinions from folks on this topic and I think too many variables for Lexus to probably want to put in writing what higher octane will (always) do for every driver in all combinations of situations, I'd suggest following what the engineers recommend and your manual says on page 107: Minimum octane Rating 87 or higher. If you elect to run 89 or 91 because you personally believe there is sufficient benefit to offset the increase you have to pay for it, Lexus and your RX won't complain. I personally would save my money and run 87 in a RX350. I run only premium as my manual suggests for my RX450h. Good luck with your decision.