Many people use a high octane gas when fueling up.
But with the high gas prices, many people are going with a lower octane gas. Eric Plunkett, a service technician with Castrol Car Care Center, says a higher octane is best because it's burns cleaner. If your car's manual tells you to use a higher octane, you should. But if it doesn't you can get away with using a lower octane. But Plunkett says it's a good idea to use a higher octane, every once in a while, to clean out your fuel injectors.