Are there any potential negative side effects of mixing octane? The gas station on post was out of regular and only had the mid grade stuff. I had less then half a tank of regular and topped of with mid grade. Car seems fine. Is this okay?

 

you're fine.

 

itll run, but it wont be as efficent as it would be if you put regular in it

 

Cool. Thanks guys.

 

Yes, you've horrible altered things. Now, you're running 88 octane! Eeeeeek!

Just kidding. You're cool.