1997 SE surging

for some reason when I first start the car pull it into drive and press the gas the car will surge between 1000 and 1500 rpm's for about 3 seconds and then it will be fine. the only thing wrong with the car is that the 2nd o2 sensor is shot and needs replacing, but i dont see why that would make the engine surge?

well change the o2 sensor then, thats the problem