I have an 08 si coupe. I was better much on E this morning when I filled up. 330 miles on this tank of fuel. Filled it up and told the guy premium. I live in jersey so we can pump our own gas. I went inside the storeand car was full when I came out. He told me he didn't have a slip for me because of an error message. I wasn't worried about it. I did notice it was a little cheaper then usual. The car I believed was filled with regular gas. 11.5 gallons. I always run 93 in it. Should I go back and raise hell or just get an octane booster and not beat on the car til next fill up. I put over 300 miles a week on my car. I have about 60,xxx miles on the car. Any help would be great. I only driven the car about 6 miles since I filled it up
Thanks

 

It won't bother the car at all, just drive it out.

I skip around with my fuel use I run premium when I get it at a good price but mostly I run mid grade.

There is a 1 or 2 MPG decrease using regular fuel