BLUEGXLVCR

It's totally a valid point. I didn't read the owners manual as I had an 06 4Runner V8 which is the same engine and tranny down to compression and all. I did research that before moving into the GX. The powertrain was a huge plus for for me and I didn't want to loose that in the GX. I assumed the lack of the "premium fuel required" sticker, and same engine tranny would require the same "ding ding". I'll switch but only to see what happens. My GX runs like a champ now on midgrade. I've never run 87 or 85 if you are in Denver.

Gbrewer

common belief has been...

-Power loss
-Gas mileage itself usually outways the cost in the fuel difference
-possible triggering of check engine lights (I see it all the time here at the MINI dealership, not a lexus but still)

BLUEGXLVCR

I'm no mechanic, but that check engine light would be a result from pre-detonation coming from a knock sensor no? I'm just wondering is all. I have been using midgrade but have to qualms about stepping up to Premium. Just didn't know I had to.

cssnms

Just to weigh in on the debate... There is a distinct difference between a manufacturer "recommending" a certain grade of gasoline and "requiring" it.

The owner's manual of my 2005 GX w/the VVTI engine does NOT "require" premium fuel which I consider 90 octane and above. Rather it "recommends" that I use a minimum 87octane. That being said, there is no harm to the engine by using a lower grade of fuel then what is "recommended." Performance may suffer, mpg's may be lower etc, but there is no risk of pre-detonation (knock) when using 87 octane. Truthfully, I have not noticed a difference in performance or mpg's when using a higher octane fuel. If there is a difference it's negligible.

Here's a snippet from Phil Reed's (senior consumer advice editor at Edmonds) Edmonds article on the matter...

"When choosing what grade of gasoline to use, Steve Mazor, principal auto engineer for the Auto Club of Southern California, said it is important to read the owner's manual carefully. The key is to figure out whether premium gasoline is "required" or "recommended." If it is recommended then a driver could opt to use a lower grade of gas, if they were willing to accept slightly reduced performance and fuel economy."

rainmn

It's probably not worth the time and effort to do it, but if you did....

I'd be willing to bet that the MPG difference you see between regular and premium wouldn't be enough to make up the difference in cost between the two. It typically isn't, assuming the MPG is measured accurately.

marekh1

How many miles is anyone getting from a full tank of premium?

easgx470

I averaged 1/2 to 1 mpg more on 93 over 89. Ran both for 3 months solid and that was my results over the same driving. I run 89 all the time now and I notice no other difference. Never tried 87 though. I have noted up to 3mpg difference with both Acura and Volvos but my Lexus never gives me that much. Plus I don't notice any performance changes on 89. My Acura and Volvo were awful on anything less than 93 but Lexus runs like a top on 89. We had the same drivetrain on our Sequoia and we always ran 87 with no issues. I am sticking with 89 in my GX.

squeege

I get 300miles & the light goes on. I love everything about the GX except that it's a pig when it comes to gas mileage. Yes, I'm still using premium & the 300 miles is a highway trip @ 78mph utilizing cruise control.

Squeege

cssnms

Compared to what?

squeege

Compared to the cars in my driveway.

The GX is terrific at doing what it does as a hauler and when I need the space &/or seating.

Squeege

rbx10

Uhmm.. felllas now I'm confused. I thought we all put the best stuff in our truck aka 93 ???
I guess I'm missing something here. so are putting either 93 or 87 in our truck and it doesn't matter ? What is the advantage or disadvantage ? With an engine of this magnitude and such sophistication, I just don't see the justification of putting regular gas in it. But you all got me thinking now...I thought I see unleaded only somewhere....I think I need to go read my manual as well.

Thanks
rbx10

ROSCOGX470

Yes it is unleaded only but not "Premium fuel required" or "premium fuel recommended" I still use 87 octane with an occasional 93 for the cleanout, although I could just use a Lucas fuel cleaner once every 3k miles. No problems ever concerning fuel system with 78k on an 04

Kymber317

Premium is the only way to go if that's what Lexus recommends.

ALAN553

[QUOTE=ROSCOGX470;6289506]Yes it is unleaded only but not "Premium fuel required" or "premium fuel recommended" I still use 87 octane with an occasional 93 for the cleanout, although I could just use a Lucas fuel cleaner once every 3k miles. No problems ever concerning fuel system with 78k on an 04[/

Just curious, how does 93 octane "clean out"

rbx10

Hey y'all check this out. My neighbor owns an infinity GS coupe. He said one time he put regular gas in it and the car would not budge. He usually put super. Isn't that interesting? ?