Sputtering My car is sputtering randomly. There is no certain time it is just random. We thought maybe I got bad gas and put in an antifreeze for gas and it is still doing it. What could it be?

No lights are on and everything else seems to be fine. I have the v6 engine. I try to notice if it is when I hit the gas or brake and there isn't any certain time it just sputters randomly.....however, it hasn't while I am on the express way. No lights are on and everything else seems to be fine. I have the v6 engine. I try to notice if it is when I hit the gas or brake and there isn't any certain time it just sputters randomly.....however, it hasn't while I am on the express way.