This morning i started up my 96 v6 firebird and i immediatly started having issues that were never apparent before. the car was idling very roughly, jerking forward. as i begin to accelerate it jerks violently, as the exhaust sounds like its skipping, kind of like how harleys sound. at idle i noticed the rpms were lower than normal, and the oil pressure was also lower than normal. could it be a loose fitting on my exhaust? could it be a bad cat? this problem was not even apparent yesterday, its very sudden. help please!!