does it idle rough? If it idle really rough you probably do have vacuum leak somewhere, but where? You would try spraying carb cleaner or starting fluid around joins and injectors. If it changes tune your getting close or have found it. Far as the other code for the O2.... Autozone guy must not have been working long because 9 times out of 10 the code will throw when running 'real' rich or 'lean'. Also, you might check the injectors and check intake for cracks.
