* Decreased performance: The engine may experience a noticeable loss of power and acceleration. The higher compression ratio in the engine requires the higher octane fuel to prevent pre-ignition (knocking or pinging).
* Potential engine damage (long-term): Consistent use of lower-octane fuel can lead to premature wear on engine components. The knocking caused by pre-ignition can damage pistons, connecting rods, and other internal parts. This damage is often gradual and might not be immediately apparent.
* Check engine light: The car's computer might detect the problem and illuminate the check engine light.
While you might be able to drive a short distance on lower octane fuel without catastrophic failure, it's crucial to avoid making it a habit. If you accidentally put in regular unleaded, fill the tank the rest of the way with the recommended higher-octane fuel as soon as possible.
Always check your owner's manual for the recommended fuel type and octane rating for your specific Oldsmobile Aurora model year.
