GenVibe - Community for Pontiac Vibe Enthusiasts

Especially at higher mileage. Everyone should be using premium gas, it's worth it for the 30 cents to a dollar more.

Welcome to GenVibe, Chance Glad you are experiencing a noticeable gain in MPG's by using premium fuel. Not everyone can say that! I for one, while driving my 2004 Vibe GT which requires Premium 93 octane, "cheat" every tank or two and fill up with regular instead. A few years back, I performed a scientific study where I was driving 64 miles one way (128 round trip) to a job site for 5 months consecutively. Driving the exact same path, the exact same speed, and mostly the exact climate, I found ZERO change in MPG's between using regular vs premium. No spark knock or other performance issues were noticed. So to this day (60,000 miles of driving since I purchased my older Vibe GT six years ago) I routinely fill up a couple tanks of regular to a tank of premium. All goes well and life is good.

I can see where higher octane would help a the higher compression GT/2ZZ, especially in lift, but running higher octane in my base had no effect. I also accidentally ran a tank of no ethanol gas through it once, for a huge price premium, but had no performance or mileage benefit. But I don't drive hard. Around me, 93 octane runs about $0.80US/gallon more than 87 octane. No way would i get 25% better mileage out of the higher octane.

But I don't know what kind of Vibe you have or what condition its in. If you really see marked better performance out of yours with the higher octane, perhaps there is some other lurking issue with it that the higher octane compensates for.