Idle speed is controlled at the rotary idle air control valve stuffed between intake runners 3&4. Pull its plug and see if the idle speed changes - if not, do a search here to find out why. The OVP fuse may be bad, disabling the ECU, the throttle position switch might not be making contact, the linkage may be hung up, the ECU could be bad, or the valve itself could be gummed up or no-op - to list a few.

Steve