Ford: Idle speed issues, speed issues, speed changes

Question
2004 Ranger V6 manual transmission.  The problem I will describe is intermittent, but seems to be getting worse.  Normally, upon depressing the clutch, the rpms stay for a couple of seconds while shifting and drop to 1000 upon holding clutch in and drop on to 600 when stopped.  The problem is that some of the time, the rpms want to stay at 2000 or above.  For example, upon shifting into 2nd and then letting off of the accelerator when traffic slows but the truck doesn't slow down.  Other times, when depressing the clutch, the rpms will stay anywhere from 1000 to 2500 - it may go down or it may not, until I release the clutch.  Once at a drive thru, it idled with clutch in and out of gear at 2000 rpm for the entire transaction.  Dealer could not get symptoms to duplicate.  No codes, no engine light.  Any suggestions?

Answer
Hi


Idle is controlled by an IAC (idle air control) motor.  This motor is common for acting up when warm and causing all kinds of idle issues.


The only way to catch it is get the truck very warm, keeping the hood closed and when it acts up, open the hood quickly and tap the IAC and see if idle speed changes.

Or  replace it and see if problem returns.