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High octane gas usage

I own a Lexus IS250 which on the gas cap says you must use high octane gas. My question is, do you REALLY have to use High octane everytime you gas up or can you safely use mid grade? Say every other time without damaging anything?

What, exactly, does the gas cap (actually, the owners manual) say? “Must” means must…

Using Regular when High Octane is required.
The BEST case scenario…

Vehicle will experience less performance and a drop in gas mileage.

WORSE case scenario…

Knock sensor doesn’t work properly and doesn’t detect engine knock when you’re using 87 octane. As you drive up-hill engine is knocking horribly…Then WHAM…You blew a hole in one of your pistons…thus destroying your engine.

It’s unlikely that you’ll destroy your engine…but there’s a chance. And why take the chance for a little savings (if any because of the lower gas mileage).

If you can afford to buy a Lexus…they why are you complaining about using high octane.

If the gas cap and the Owner’s Manual state that high-octane gas is “required”, that seems pretty unambiguous to me.

On the other hand, if it merely uses the word, “recommended”, than you can safely use lower-octane gas.
However, you will get fewer mpg as well as less power for acceleration.
The reduced gas mileage factor actually makes this a non-starter in terms of saving money.

So–did the manufacturer state that high-octane gas is recommended, or that it is required?
If it is the latter, what part of “required” do you not understand?

This question comes up every time there’s a spike in gasoline prices.

Yes, you must use premium if premium is required.

Premium cars usually require premium gas. It’s part of the ownership costs.

This question is beat to death here. Please use the “Search” button above.

If you can’t afford the correct gasoline, you certainly won’t be able to afford the correct maintenance on this car. Maybe you should trade it for a Camry while you still can.

On any of the IT Forums I frequent any person (whether member or guest) would be incinerated for asking a question so easily found using search. I am certain ths situation exists as it does here because of the atmosphere portrayed by the show. It is not totaly bad that people do not use search, it reaffirms our beliefs about the general public.

You may find that switching to a lower grade gas could cost you more money.

While switching to mid-grade may be saving you about 2.5% at the pump, if your mileage drops by more than 2.5%, then that “switch” is costing you money.

If your car normally gets 20 mpg with high octane and switching to mid-grade causes it to drop below 19.5 mpg, then it’s costing you more.

One reson for patience - unlike almost any other forum, there’s no FAQs section…MUCH NEEDED!

And since it was designed for premium, you likely are getting lower mileage than if you used premium so you may be paying more for fuel while risking some expensive damage.

premium car means premium fuel. You’ll likely only save $3 per fill up. If you can’t afford that…