I have a 2011 civic that recommends 87 octane or higher. Is it bad to put 91 octane in all the time?? Would it damage anything?
Just your wallet. For your engine, there is no benefit or danger.
You can spend your money on anything you want, but premium gas won’t help your car at all.
You are just throwing your money away. Start buying 87 octane and save your money.
Higher octane does not damage the car. The fuel is slightly cleaner and better for the car in hot weather. In moderate or cold weather there is very little benefit.
Interesting screen name . . . considering you’re asking a question about a Honda Civic
I’d save my money and use the 87. If you tow or haul heavy items in a pickup, the manual suggests using a higher octane. Neither of those is your situation, unless your mother in law is 900 pounds or over