High idle at start up

What is your question?

1,700.00 In repairs I had problem with the car reving high when I stopped driving and putting car into park it was reving to 15 rpms. The shop changed the iac and mass air flow. Now it does the opposite when I start it it revs to 18 then will slowly idle down. Repair shop said it is what it is and there are no adjustments being fuel infected. There has to be another sensor that needs replacing, car only has 82,000 miles anyone have any clue? Wth?

What makes this problem better or worse?

It happens only at startup

How long has your 2002 Toyota Corolla had this problem?

A month