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I live in Western Michigan and spoke to a fuel deliver man who is a customer of mine. I asked him the diff between 87 and 89 octane cause many stations in this area sell them for the same price. Was wondering the advantage or harm of using 89 octane in my 04 ex sedan. He said all gas in this area comes from one pipeline and is mixed with ethanol to raise the octane level to 89. That's why they're the same price. He said there is one station he knows of that sells unadulterated 87 which he recommends for older vehicles. I'm buying ethanol boosted 89 regardless of which pump I pick. Does this mix harm my Civic? Is it legal/ethical that I don't have a choice of 87 octane? Do the tier 3 stations use pure gasoline?