hook you car to a scan tool and see how fast your o2 sensor voltage fluctuates, it should be pretty fast, oh and they wont move very fast until the car is in closed loop.

2002 Cougar 2.5 duratec/ mtx-75 85,0000 Mondeo ST-200 wheels/BFG KDW NT black/black Spec Stage 1 Torsen T-2 Trubendz 2.5 flowmaster dual exaust apexi s-afc II K&N FIPK