Unplug the Throttle Position sensor, but do nothing but idle. The PCM should recognize the ~0 volts from the TPS as an error (~0.9 volts is its idle value), and air control at idle is only done though the IAC. The car would likely drive VERY poorly if you tried it then, but you shouldn't need to do that to throw a CEL. Mght need to idle for 5 minutes, shut off, then idle again though.
