Said It Here

Is premium gas actually necessary if my car recommends it?

Using a lower octane than recommended can cause engine knocking and reduce efficiency, but cars designed for standard fuel do not benefit from paying extra for higher octane. Check your owner's manual to see if premium gas is strictly required or just recommended, as using higher-than-necessary octane wastes money without improving engine performance.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    running lower octane fuel like 87 and letting the car's computer adjust parameters to compensate
  2. 2
    Following the manufacturer's recommended octane rating
  3. 3
    Letting others spend their own money on higher octane fuel if they insist

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/AskMechanics2 people · September 2026

“My roommate is adamant that her 2004 Corolla needs 98 octane fuel as it’s “better for the engine”, despite the fact it recommends 91.”source ↗

LobsterQuirky3634 · r/AskMechanics · 4 upvotes

“I was talking about my car and how it takes 91 octane gas and how it’s kind of annoying but they said that it wasn’t really necessary to fill it up with premium. It got me thinking if it really is or isn’t necessary to use premium gas in my car.”source ↗

DefaultUser1547 · r/AskMechanics · 1 upvotes

Where this came up

People with this problem also raised