You need to imagine it as it is true. I worked in the Texaco Regional accounting office for years and the tank truck have separated compartments.

My local BP station says that the regular tank gets filled 5 times more than the premium tanks due to the cost difference. Octane does deteriorate with time.

 

Costco doesn't have octane booster at the pump but interestingly enough, they have a unique system to inject their fuel additives (detergents) at the pump onsite whereas most other stations have it added at the depot. This allows them to get the lowest price.

 

The car was engineered to run on a MINIMUM of 91 RON or 87 at the pump so it is design to run BETTER on a higher octane. The computer compensate for lower octane, but it never cease to amaze me how people interpret the wording in the manual, as if one MUST use the 87.
I use the middle premium just to be sure, I keep my vehicles for a long time

 

Keep in mind that any performance benefits from using a higher octane fuel with happen over several tanks of gas.
The computer is designed to make small adjustments as needed. So dont expect any immediate results.

 

I been using Regular in my 2017 RX350 for last 5 months and ride has hesitation and knocking since Day 1. Last 2 tanks I switch to Shell Premium and can see the difference. SUV seeing very less hesitation and much smoother to Drive and hardly any knocking.
I think Lexus Sales guys should stop telling people to use Regular as its no fun driving these expensive SUVs on a Regular Gas. I think its a Lexus Sales Gimmick to attract more customer by advertising that the car will run on Regular and no need to use premium.
I am sure Car will run on Regular but with a ride full of knocking and hesitation... I am thinking to try 89 also and see the difference between 89 and 91.

 

I've used 1/2 tank of the fill-up that came with the car and have not experienced any hesitation, but I don't know what octane they filled it up with, I assume regular 87, when down to 1/2 I filled with premium 91 and when down 1/2 again I filled with premium. The car was designed to run as low as 87 if you are experiencing problems I would change gas station 1st just to see if elsewhere the fuel is better and if it persists I would take in for service, it should still be under warranty. The computer should make the engine run smooth by altering the timing.I have the same car & year.

 

Sorry if this has been discussed before, but I couldn't find it. I know that the Top Tier gasolines in all grades (I use Exxon-Mobil) promise sufficient additives/detergents to protect the engines. But still, is the additive packages greater in premium vs. regular, or is it exactly the same in all grades?

 

I've used Shell regular in my '16 since day 1 and have never experienced hesitation or knocking.

Have you talked to the Lexus service manager about the problems you've been having using regular?

The fuel requirements are determined by the manufacturer and not the sales people. I'd be upset if I had to spend $15 more per tank (regular vs premium) to get the car to run correctly.

 

I would get you vehicle to the dealer as it should not knock on regular!.

As far as the hesitation, I remember it well when I had my 2016 RX350 and it was due to the tranny keeping it in too high of a gear in my opinion. Nothing to do with the gas.

Like I said before what gas you use is up to you, but most of todays vehicle just plain do not care.

ALSO, The "knock sensor" is dynamic and does not take several tanks to adjust, it is listening for the knock and takes appropriate action instantly.

 

No knocking or hesitation in my Lexus. Perhaps something amiss in your car.

 

Yes the additives are present in greater number in premium than regular, it's these that contribute to the higher price, the xtra refining only a little bit.

 

it shouldn't knock at all..the system will adjust timing and performance and it happens as soon as there is any hint of impending knock...it would be unlikely that it would actually knock unless there is a defect in the knock sensor and system. Keep filling consistently with 91 and you should see an improvement.

 

I think those knocks might be more droning and humming then real knocks. So I might have said it wrong when I mention Knocks. But Hesitation is definitely improved in lower gears with 91 and in Higher speed like 55+ it Cruises more smoothly..
Other thing is when you turn right from a dead stop it makes that noise also even in Sport Mode.

 

my old 06 is250 awd ran 87 gas for 125k miles no issues...

anyone care to add how altitude has an effect? I live at 6000ft asl. many sell 86 octane and not 87

 

OK, several of you are saying the change to 91 gas will show an immediate improvement. Other are saying it will take 2-3 tanks or more to show any difference. Which is it?