If a vehicle recommends 91 Unleaded gas, can you still use 87 Unleaded?

Question

I am looking at the FJ Cruiser... and I saw on the gas door it recommends premium. I have looked around online and have read about people using 87, 89 or 91 in their tank. What are the negative effects of doing so, especially since it recommends Premium????

Answer 1

You can if you want,  but you will get poor performance, engine knocking or pinging, and shorten the engine life.   Use the recommended fuel!   You could void the warranty of your engine-  And Yes we can usually tell by looking inside the engine if it was pinging

Answer 2

I'm dealing with the same situation with my Acura Mdx. I took it to a local car care center and they told me using 87 octane can increase your chances of engine knocking. It's almost the same thing because 93 octane burns a lot slower so you'll run on the same tank of gas for a longer time.

Answer 3

We recomend use of prem. gas, but the engine will re-learn the regular if you use it.  Don't switch back and forth though.  You may experience light engine ping on hot days though.

good luck