I've got a 2007 Chevy Cobalt LS Coupe 2.2L. For the past few weeks it's been making a strange sputtering noise when I accelerate. It started as just a light chirp under the hood which made me think it could possibly be my belt. So I took the belt off the tensioner and checked it for cracks but nothing. Now it's evolved into something much louder and more serious sounding. It gets louder and sputters more as I accelerate. It almost seems like the car isn't getting a steady flow of fuel....... possibly the fuel pump. idk. I've also noticed a stronger smell of emissions coming from under the car (that could just be me being paranoid) which makes me think maybe it has something to do with the exhaust system or the catalytic converter itself. The check engine light hasn't come on and the car only has 56,000 miles on it so it shouldn't be anything too serious but it sure sounds that way. Anyone else have this problem or any advice they can give?