Hey I go to grad school at Marist in Poughkeepsie...neat...anyway, not many Z mechanics around these areas. But if it is running rough on and off it is probably a cylinder firing/not firing...either due to an injector connector/coil pack connector. Before spending any money on some clown mechanic, try pushing down all 12 connectors (coil pack connectors/injector connectors). If it is still intermittent, locate which cylinder is the problem and it more than likely is an injector or half broken wiring