I put 91 during the breaking period since i kinda drove it hard during that time. After breakin, i switched to medium 89 grade...

 

The owner's manual says the 4RX only needs 87 octane, so I'm going with that. Unfortunately, the stations around here only have 86 or 88, so I have to buy 88. Also, I switched to Top Tier gas when we got our 350. If you look up gas stations in the navigation system, 15 of the 21 brands listed first are Top Tier brands. I'm wondering if those are the brands recommended by Lexus/Toyota.

----------

TOP TIER Detergent Gasoline is the premier standard for gasoline performance. Seven of the world's top automakers, BMW, General Motors, Fiat Chrysler Automobiles, Honda, Toyota, Volkswagen, Mercedes-Benz and Audi recognize that the current EPA minimum detergent requirements do not go far enough to ensure optimal engine performance.

Since the minimum additive performance standards were first established by EPA in 1995, most gasoline marketers have reduced the concentration level of detergent additive in their gasoline by up to 50%. As a result, the ability of a vehicle to maintain stringent Tier 2 emission standards have been hampered, leading to engine deposits that can have a big impact on in-use emissions and driver satisfaction.

These automakers have raised the bar. TOP TIER Detergent Gasoline help drivers avoid lower quality gasoline that can leave deposits on critical engine parts, which reduces engine performance. That's something both drivers and automakers want to avoid.

TOP TIER Detergent Gasoline Retailers must meet the high TOP TIER standards with all grades of gasoline to be approved by the automakers as providing TOP TIER Detergent Gasoline. In addition, all gasoline outlets carrying the brand of the approved retailer must meet the TOP TIER standards. Additional gasoline retailers are added to the TOP TIER list as they meet the standards. The retailers known to be on the TOP TIER list are shown below.

U.S. TOP TIER Gasoline Retailers:
76 Stations
Aloha Petroleum
ARCO
Beacon
BP
Chevron
Cenex
Conoco
Costco Wholesale
CountryMark
Diamond Shamrock
Entec Stations
Express Convenience Centers
Exxon
Hawaii Fueling Network (HFN)
Holiday Stationstores
Kwik Trip / Kwik Star
MFA Oil Co.
Mobil
Ohana Fuels
Phillips 66
QuikTrip
Road Ranger
Shamrock
Shell
Sinclair
Suncor Energy Inc
SuperAmerica
Texaco
Tri-Par Oil Co.
Valero

 

I've heard regular and I've heard premium, what do you guys say?

 

RX 350 is regular. RX 450 is premium.

 

Sounds good

 

I did notice non ethanol regular gave me slightly better mpg than just regular or premium unleaded. I have a few station close to me that offer non thanol 89 octane fuels at a little below premium unleded. I guess I will keep using when I can.

 

I would rather use shell non enthnol 89. But that cost us 10 cent more than premium.

 

I use premium, car runs smoother. Sometimes mid grade never use regular gas.

 

It's not a 450H.

I ALWAYS use COSTCO regular gas. Zero problems. SMOOTH as butter. I'm at 8,000 miles, no vibrations, issues, cold start problems, etc.

Later, before every oil change, I'll add the Chevron Fuel cleaner just to keep things nice and smooth.
Also, a lexus tech told me to redline my car every once in a while to clean out something, may have been the fuel injector? Make sure the car is properly warmed up first and do it while driving maybe getting on a highway.

BTW, I had a toyota solara 2005 and always used costco regular gas as well with zero problems. Going strong at 200,000.

 

The chevron Fuel Cleaner in stores is snake oil. Probably does absolutely zero for your car. If you want a fuel additive, try using this. https://www.amazon.com/BG-44K-BG44K/...ds=bg44k&psc=1

Also running the car hard (redline) every once in awhile does help get rid of build up....especially in the Direct Injected engines. I do it at least once a day.

 

thanks for the tip!

 

Alcohol has about 33% less energy than gasoline so at a 10% blend ethanol has about 3.3% less energy & that should result in 3.3% better mileage with non-ethanol. If the price was $2.50 a gallon that would make the break even about 8+ cents. So you could pay $2.58 for non-ethanol in theory to break even. Since alcohol is corrosive there may be other advantages to running non ethanol but that's another story.

 

Wish they would stop putting alcohol in our gas. It does noting good except fatten the corn growers pockets. The EPA even was against it as growing the corn was not good for the environment, but money shut them up.

 

Thanks for the info. I was aware of the percentages of savings and the break even point. The main reason I try to stay away from ethanol fuels is because I have seen first hand what it can do to pretty much anything that is not meant to run ethanol. I also know most modern cars can handle ethanol now but for me I just think of it as a little insurance

 

Same here, I never use regular I prefer using premium because IMO it runs better. No scientific data, reports etc., just my experience using premium fuel.

Come to think of it, the last time I used regular was 3 years ago when I had a rental for business. The only time I even think about regular gas is when one of these threads comes up..