If you put 93 octane gasoline instead of 87 octane gasoline in your vehicle then your vehicle will run just fine.
The cars engine computers can usually adjust their timing to account for the increased octane levels, so if you put premium gas in a regular car, you probably won't notice anything.
However, some engines are not designed to burn higher-octane fuel, and you may see a reduction in performance and fuel economy.
And mixing 93 and 87 gas doesn't have any ill effects.
It simply creates a new formula referred to as “midgrade” that's often available in gas stations.
Additionally, the difference between premium and regular gas is that the premium ones are of higher quality.
If you put premium gas in a car that doesn't call for the expensive stuff, it won't affect performance, burn cleaner, or improve your fuel economy.
So unless the manual suggests premium fuel, the rule of thumb is to avoid spending that extra cash at the pump.
Can 93 gas damage engine?
Using premium gas for your vehicle will not hurt its internal combustion engine.
If your car is meant to run on regular octane gas, filling it with premium gas causes no damage — other than to your bank account.