I'm getting my 2007 chevy cobalt ls repaired this coming Wednesday, but my car was diagnosed with a cracked manifold and that's why it's been loud! But my car when I start it sometimes it sounds like a Corvette running. And it's a 2.2 L 4 cylinder! I thought bad gas but put treatment in and acted better for 2 days then it shit on my today and wouldn't start and I wasnt pushing the gas and flooding it out. Uh nah F.T.S.!