Higher octane fuel isn't necessary until detonation (knock, misfire, call it what you will) starts occuring. If you have a scanguage you *should* be able to find a field called knock counts or spark counts. Typically the computer will register a few on startup which really aren't of any concern. If this number keeps climbing during normal driving then bumping your gas up to a higher octane rating can help. I'm more familiar with OBD-I systems as opposed to the OBD-II systems, but the ideas are the same; no reason to run higher octane gas if it's not detonating and there's no reason it should under light driving.

2007 Saturn View Greenline 30 mpg ftw!!
1992 Camaro, Small block, Nitrous, 5 Speed, not exactly a green machine but definitely a fun toy for friday nights!

Coming soon....
MR2 EV conversion!