high RPMs coming to stop

[hr8882]

I have a Ford Ranger 3.0L MFI. When I come to a stop the rpms stay 1300-1500 for about 30 seconds after stop then comes down to 700, its hard on the vehicle. its hairy in traffic coming to a stop. i have no codes or pending codes, I've cleaned the throttle body and
plate. if I plug the IAC the problem goes away although the base idle is at that point to low. my question is that in my experience faulty IACs don't cause the symptoms I have, Rather if they stick open they cause a dying at idle or if they are stuck open cause rpms to stay high. is it possible that the valve is sluggish? Thanks for viewing.

 

[rusty ol ranger]

Since the RPMs dropped off it sounds like IAC is working.

It sounds like you have a vaccum leak

 

[helpme]

Check those little 1/8 inch plastic vacuum lines. The break right there where they go into the adapter for the 3/16 inch fittings. That's where my vacuum leak was. I just changed them with 3/16 hose and eliminated the adapters.

 

[RonD]

There is an emissions requirement on manual transmission vehicles that holds the RPMs high while shifting or when stopping

RPMs should stay above 1,000 until speedometer is below 5MPH

If that is what is happening then its "normal"

If you are driving at say 2,500rpm and push in the clutch pedal and hold it down, RPMs should stay high for 5 to 7 seconds, then drop to the 1,300-1,500rpms you have now
You may not notice this when shifting gears but it should happen

Engines Idling under 1,000rpms have to be run richer or they will overheat, and richer means more pollution so idle is held high as long as practical

And this is why we have Auto Stop/Start now on newer vehicles, they couldn't meet idle emissions unless they were turned off

Just a heads up, you might check with Ford Dealer and they can look up your VIN to see if there was a software update for your 3.0l Ranger Computer
I remember there were high RPM issues in the early 2000's on some Ranger models
Because of its age they may not be able to do the update of won't want to, lol
But you had to pay for the update in any case it was never a warranty or recall issue