why is my car idling high?

What is your question?

it slowly started to idle up one day at first thought it was just cause of ac running in 100+ temps within 4 days it idled 3000-4000 rpms especially at stop lights first second then 3rd now 4th when in 5th gear seemed to run fine.now I am afraid to drive even in 5th with high idle. we have replaced the air flow sensor, checked the vaccuum leaks for leaks disconnected battery and tried adjusting the idle to no avail. the check engine light is not on and has not come on at all. what else should we be looking at? we removed the intake hose and for a minute it idled down to normal but as soon as we put our finger over it it idled right back up to 3000-4000 rpms. Help single mother of 3 plus gbaby and only mode of transportation to work.