Not a good idea to run 87 octane in an engine that requires 93 octane. It will predetonate in the cylinders producing a lot of knock, may cause damage to the valves and head as it will generate more heat. Also, the engine won't develop enough power or torque as it should. You would be giving it much more throttle, it will knock and ping, and your fuel economy will suffer. I would suggest that you use the right octane that is spec for the engine.

 

ok thank you for the information on that. i think i'll stick to a F22.