High Idle

[2002Ranger]

My 2002 Ranger FX4 5 speed with only 62,00 miles sometimes idles high in between shifts and won't come down for 5-10 seconds. This is very irritating because I know that I am prematurely wearing out the clutch everytime it happens, and it's just plain annoying having random problems that nobody has a good answer for. I don't have any codes on it, had a decent mechanic look at it, and I changed the throttle position sensor- all without results. I have the IAC valve in a box ready to be installed, but I hate throwing parts at an inconsistent problem. I also am getting poor gas mileage (15-17 highway, 12-13 city) and I would consider my driving habits to be very economy minded. Could these two problems be linked? Any suggestions?

 

[was_shaggy]

Is your IAC in two parts? The IAC motor and the spool valve? If so take the little motor off and see if the spool valve moves freely. They will get carboned up.
apply carb cleaner liberally to the spool valve. Hope that helps.
As always look for wear patterns. If they get cockeyed the won't move right.

My 4.0 is a 91, it's idleing high with a new IAC on it. Gonna have to get out there with a DVOM, do some probing & get some numbers. But it's gonna rain next two days.

In the mean time