Plugs are probably still good. I changed mine at multiples of 60,000 and the old one always looked good. The wires were not replaced until 150,000 miles and they still seemed fine.
I do suspect that besides cleaning the throttle body that you would benefit from cleaning the intake manifold. There is a FAQ for how to do it on the car.
http://www.contour.org/mods/mods.php?s=howto&displayid=43 
