* Reduced Performance: The engine's computer will likely adjust the timing and fuel mixture to compensate for the lower octane rating. This will result in a noticeable decrease in power and acceleration. The engine may feel sluggish or hesitant.
* Detonation (Knocking): This is the biggest concern. Lower octane fuel is more prone to premature ignition (exploding before the spark plug fires). This detonation can cause a pinging or knocking sound from the engine. Prolonged detonation can severely damage engine components, including pistons, connecting rods, and the cylinder head. This damage can be expensive to repair.
* Increased Fuel Consumption: The engine may run less efficiently due to the adjustments made to compensate for the lower octane fuel, potentially leading to slightly worse gas mileage.
While the car might run on regular fuel for a short period, continued use will significantly increase the risk of engine damage and reduce the lifespan of the engine. It's strongly advised to use only premium fuel in a 1997 Oldsmobile Aurora. The cost of repairs from using regular fuel far outweighs the savings on fuel.
