Does a 96 Cadillac STS require premium unleaded?

6 Answers

  • 1 decade ago
    Best Answer

    It is recommended for premium, however after 13 years, the compression has probably dropped to the point where it wont make any difference. Fill up the car with regular, and see if the engine knocks. If it does, when you are half empty fill it with premium. If the knocking stops, then start using 89 octane gas. If it still knocks you will have to use premium.

    Remember, premium does NOT give you better gas mileage. So buying premium because you think it is better for your car, is a waste of money. Use whatever gas that does not cause knocking.

  • 4 years ago

    Your car wants higher octane fuel because of a higher compression ratio. The higher octane fuel resists detonation better than the lower. If you notice a lot of knock and ping switch to the higher octane fuel or use an additive. Excessive ping can leak to valve and piston damage. Essentially you have a mistimed explosion happening in your engine that inhibits the normal operation of the engine.

  • Anonymous
    1 decade ago


    300 horsepower engiens do require premium.

    You can run relgular, but the knock sensors will retard the timing and you lose MPGs and performance as a trade off.

    Pick your poison.

  • bobweb
    Lv 7
    1 decade ago

    Even if your car's owner's manual says so, you should try using regular gas and see if the engine operates normally.

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  • 1 decade ago

    No. You'll be just fine with 87.

  • 1 decade ago

    your book that came with the car should tell you.

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