the reason i ask is because i had a sc cavalier, i know ewww, but we all start somewhere. anyway i had simlar problems and it ended up being the sc coming apart inside and the result was, at first at least, that i had a lack of power and sluggish starts which it didn't do before. and eventually came apart enough to put a hole one piston. its just an idea and i dont know how you would really check it but if it helps great. good luck.