With clutch pushed-in, RPMs start to go up to around 2000-2500

I have 1987 F150 4-speed Manual 302cc. It didnt always do this. I am going to do research in to the fuel pressure regulator, Idle air control valve, &/or throttle position sensor. I will post my findings.

My F150 problem is: when I start the vehical it runs like a used kitten (this is a good thing at 200,3000) Then as it warms up, just at idle, RPMs start to go up to around 2000-2500. If I pound on the gas peddel the RPMs will drop back down to normal idle. However, I will start to drive to work, running just fine on down the road. Until I come to a stop and push the clutch in. The RPMs will climb back up to 2000-2500. So, I try my pound on the gas peddle thing, and they go up to 3000-4000 RPM and hold steddy for 20 sec. or so. Then climb back down, but not all the way down to idle. I thought perhaps pre-detination due to carbon buildup or something, but it idles fine and runs smooth even when it it running high.

People keep telling me there is a air leak or something like that some where in a pressure line, but I see nothing. So I am going to start by cleaning and inspecting the Idle Air Control Valve (IAC). on WWW.2carpros.com has a DIY on how. Just google it and you will see.
~Decker