Thread: Seafoam

I guess it could be my driving cuz I'm a little heavy with my foot. But I would've thought that these grand prix get a little bit better gas mileage. I always put 93 octane in her so I'm not sure lol.

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I've ran both just to see if there is a difference and there is no difference in fuel mileage between running 87 and 93 in a Supercharged Grand Prix. If I drove it harder there may have been a difference due to the different timing tables, but as it was, the difference was nil.

I continue to run 93 though because $100 a year more in gas is better than replacing an engine because of possible knock damage.