Can the need for an oil change affect gas mileage?

The oil life in my 2005 Chevy Cobalt is at 12% and I feel like my gas mileage is suffering.Can the need for an oil change affect gas mileage?
what that means is your getting close to your oil change, you start out at 100% and go down from there and your computer in your car will let you know when it is time to change it. Colbalts get decent milage. Your gas milage isn't suffering, if you want to increase your milage and go a little longer between oil changes, switch to synthetic oil your milage may increase a few miles per gal.Can the need for an oil change affect gas mileage?
what do you mean your oil life is at 12%? are you basing it on mileage, or on age? yes, dirty or contaminated (too thick)oil can affect your gas mileage. there can be alot of things that can affect gas mileage, air filter, gas, low air pressure in the tires, time for a tune up, etc., etc. how many miles do you have on the vehicle?
Chevy cobalts are not great on gas anyway. Probably one of the worst small cars on gas. Get your oil changed for goodness sake. Take it to the dealership or to Midas, pay 25 bucks and get peace of mind. You are driving a general motors car. Your best bet for getting the most years you can out of it would be to change the oil regularly- every 4K miles or so.
Well you wouldnt notice it if it did actually affect it. If you feel like its worse, check tire air pressure, air filter and tuen up parts