My 1998 ford taurus overheats when idling but cools down when you drive what should I do?

Check your your radiator cooling fan should come on at about 220 deg. and off at about 210 deg. at idle with a/c off, if it stats to over heat turn a/c on, fan should come on right away, if it dont check voltage at fan motor, if you do have voltage, you have a bad radiator fan motor, more then likely the reason it don't over heat while driving is air is being push through radiator where it cool's the coolant before it goes back into the engine, at stop's no air running through and never cool's coolant .

Make sure the water pump is working by checking the flow through the rad when cool. The rad may be blocking & you may not have enough coolant. Also check the condition of the serpentine belt for wear & cracks, you may have slippage because of the belt. Your rad fins may be loose & you may need a new rad. Check these items & good luck!