You need to tell us how you have it wired and where you are measuring the voltage. For the most part all common narrowband O2 sensors are functionally similar. Once warmed up the heater circuit shuts off and you should be measuring between the white wire and ground. Also you must use an analog meter as typical digital meters do not respond fast enough to see the switching. If the 320Mv is correct then you probably have something causing the lean condition. Vacuum leak etc... There is no reason I can think of why I would EVER add a resistor to that circuit and expect it to work.
