Originally Posted by coalslaw
Stating the obvious here, any STI owner would be smart enough to not run 91octane or mixed fuel or octane booster or any of that crap. you should be running 94octane. mixing fuels will only confuse your ECU. it could be that you had 94octane when you went for your protune.
And I'd figure most STI's owners would know that not every state carries above 91 octane in most gas stations. Way to prove me wrong.
91 is perfectly fine, not ideal, but it works fine stock or if tuned for it.