My 2013 Chevy Cruze has an engine light on and seems to run rough 50% of the time now. I thought it was the gas cap, and replaced it. The engine light went off but is now back on again. I stopped the other day to get gas at a local gas station and when I started up my car, it almost cut off and was running so rough I didn't think I would be able to get home. Anyone know of what is causing this?