cables ok, coolant level ok, have not checked air control motor. codes P0 300, 301, 302, 303, and 304 show up which are cylinder misfire, check engine light does not come on. think it may be narrowed to to air control motor.
Idles too high on 2002 Toyota Celica
Disconnect the idle air motor and see if the idle goes down, that is one way to check that.