sounds like your CIS system is not working. Yes it could be the switch on the throttle. If you have a multimeter you can check it. With the throttle closed there should be no continuity with ground. Throttle open ... continuity. It could also be the air idle valve. It could be the wiring, it could be the control unit. A quick basic test to see if the system is operating is to unplug the temp sensor wires under the 4th intake runner. If you do this the cars idle should go way up to about 3000. If is goes back to normal when you plug the sensor back in your system is probably working. It is actually easier to unplug the temp sensor wires at the 8 wire connecter block on the passenger side. The temp sensor wires are blue and red. You can remove individual wires from the connecter (there are 2 flaps on the grey block that unsnap to do this). If you can't identify wire colors here you probably need a new wiring harness.