The water pumps on the four cylinders don't seem to be as troublesome as those on the six cylinders. If your temperature was fluctuating widely, I suspect the problem is not with the water pump. There are a lot of things it could be, including the thermostat and the electronic temperature sender. At one time the gauge on my zetec was fluctuating drastically, and the problem turned out to be the sender. The temperature itself was staying constant, but the gauge was bouncing around like crazy. If you're lucky, that will be the case. It's a cheap and easy fix. Replacing the water pump on the zetec is neither cheap nor easy.
