so I own a 06 cobalt lt sedan and its been making some odd sounds and seems to slowly be getting worse at start it sounds really loud till warmed up and after warming up idle gets jumpy like a miss no codes but you can feel the vibration from it when ac or fan is turned on it seems to make it worse and from the valve cover it sounds like a lot of ticking/tapping going on sounds to be coming more from trans side but still there on belt side also their is 180000 miles fresh oil and filter tb gets cleaned regularly