If that has a turbo, check your owner's manual. I'm thinking the engine was designed for 91 octane. It *will* run using 87 octane, but the performance will be impacted. If you're worried about MPG - remember, 91 octane costs $0.20 to $0.45 more per gallon, too.
There should be a sticker on the gas fill door and on the dash and in the book that tells you what octane you need to use. Using a higher octane if you don't have to is just pizzing money away for no reason, except for stupidity.
There are pros to using 91 octane gas. It takes longer to burn and therefor your at the pump less. 2 it helps keep your engine running much smoother and therefor helping the car last longer. The cons are that when you go to the pump you are paying more for the gas so it's up to you.
If the car is rated to run on 87 fuel, using a higher octane wont make any more power.
It wont harm anything, just you are wasting money.
Would it make a difference if I use 91 instead of 87 which the dealer said I could use.
