No, but the vehicle has to be able to operate on E85.
NO! As far as I know the Vibe is NOT a Flex Fuel vehicle. If it is Flex Fuel and can burn E85 it will have a label affixed to the vehicle somewhere. Do NOT use E85 in a non Flex Fuel vehicle.
If the car is a Flex-Fuel vehicle then yes you can use E85. If it is not a Flex-Fuel vehicle you cannot use E85. Using E85 will damage components. As far as I know your 2006 Pontiac G6 is not a Flex-Fuel vehicle. Reads your owner's manual to be sure.
E85 or gas.
If it is a Flex Fuel vehicle, YES. If not, NO.
If you have the Flex Fuel Vehicle ( FFV )
If you have the 3.0 liter FFV ( flexible fuel vehicle ) engine
Yes, E85 ethanol (85% ethanol and 15% gasoline) and regular unleaded gasoline can be mixed in a flex-fuel vehicle designed to run on both types of fuel. However, it is not recommended to mix them in a non-flex-fuel vehicle as it can damage the engine. Always check your vehicle's compatibility before mixing fuels.
If you are using E85 fuel yes it will get less mileage. If you are using regular unleaded there will be no difference.
Not unless it is a Flex Fuel vehicle. Read your owners manual.
Only if the vehicle is clearly labeled as "Flex Fuel"!
You don't if the vehicle was designed as a flex fuel vehicle. It can safely burn E85 ethanol. You can burn a mixture of 10% Ethanol in any vehicle.