Yes but it will make it run rough unless you get it tuned down for a lesser grade.
It would only hurt if the car required 89 octane or 92 octane and you went to a lesser octane. Those cars are engineered to run on a higher octane. A car engineered for the lower 87 octane might actually see some performance improvement by going to a higher octane once or twice, because the higher octane will help to clean the injectors a "little". Not much though. Over all there is no real significance to using the higher octane. The higher the octane level, the "richer" or "heavier" the fuel is. So if the car is not manufactured for the higher octane, you will eventually cause carbon build up at a faster rate than normal.
octane is how volatile the gas is the higher the octane the bigger the boom and cleaner it burns
your car must have 93 octane.
Each car should have a recommended fuel octane in the owners manual.
Using octane fuel higher than your car is rated generally has minimal impact on performance or efficiency. Most modern engines are designed to run optimally on the recommended octane level, and using a higher octane fuel may not provide any noticeable benefits. However, it can help prevent knocking in high-performance or modified engines that require higher octane. In most cases, it's an unnecessary expense without significant advantages for standard vehicles.
For a 1991 Lincoln Town Car : " regular " unleaded gasoline , 87 octane
If your car says it requires gasoline with a specific octane rating ... Well, it will probably operate with a lower octane rating, but it will be very bad for the engine and for your gas mileage. However, you don't need to use an octane rating any higher than your engine specifies, and there's likely no real benefit to doing so.
no it will not as long as they are both pure gasoline.
it will only if your car requires 89. If your car is designed for 87, then 89 will provide no benefit.
No, car was designed to run on 87 octane higher octane is a waste of money for that car.
Regular 87 Octane with no more than 10% Ethanol
93 octane all the way!