my monte carlo is idling high ? I changed the idle air control valve but did not help? What else cou...

try changing throtle position sencer, and tempeture control sensor.

Yes, the PCM may not be detecting when the engine is warm enough to switch to "warm" operation, and if it's staying in closed loop mode, it's using a preprogrammed higher idle and fuel mixture to make the engine run.  See if there are any stored check engine codes as well.

Papa's spot on here, blatantly the the throttle sensor.