I cant believe this has gone on for 12 pages.
Its pretty simple, 87 is fine, 91 is fine, use whatever you feel appropriate. Timing will be adjusted accordingly.

I fill 87 because im a cheap *** and this car isnt worth the extra $$. My sc430 on the other hand will knock if you put anything lower than 91.

 

The definitive word from Lexus: Which fuel grade should I use for my Lexus vehicle? (https://support.lexus.com/s/article/...rade-shou-8129.)

I'm sure this will end the discussion, and this thread will never see another post.

 

Nooooooooooooooooooooooooooooooooooooooo!

This thread is more nostalgic than my best old sweatshirt!

Here's the definitive rule for fueling your Gen. 4 RX, and I quote the former service manager of Lexus Dayton:

"It runs on regular. It runs better on premium."

NOW, we can be done.

 

you poked the sleeping bear!

 

Just follow the darn owners manual! How much longer does this need to be discussed?

 

You had me at: "Recommended Minimum"

 

This discussion requires few bottles of wine with good cheese.

 

I'll skip the discussion and stick with the wine!

 

If you really want entertainment, go to the 2nd gen NX board and see the same conversation. Especially about the turbo 4-cyl.

 

Got this from my user manual (RX MY2017)

Engine
Model 3.5 L 6-cylinder (2GR-FKS)
Type 6-cylinder V type, 4-cycle, gasoline
Bore and stroke 3.70  3.27 in. (94.0  83.0 mm)
Displacement 210.9 cu. in. (3456 cm3)
Valve clearance (engine cold) Automatic adjustment
Drive belt tension Automatic adjustment

Fuel
Fuel type Unleaded gasoline only
Octane Rating 87 (Research Octane Number 91) or higher
Fuel tank capacity (Reference) 19.2 gal. (72.5 L, 15.9 Imp. gal.)

 

Hope everyone READS this!!!!

 

lock this thread!

 

i'm sure this vehicle can use both regular and premium with no engine harm. but from my experience, the range suffers when using regular gas compare to premium. not much, but it's noticeable.

 

87 in my lexus
93 in my vette