Excessive high idle at startup

I've been having an issue with my truck where when I start it up it instantly shoots up to 2000 RPM, then after about 10 seconds it drops to 1500 RPM and stays there until it warms up, now this wouldn't be bad, but it takes about 5-7 minutes of 1500 RPM which makes those first minutes of shifting (5 speed) nasty, and makes me feel like I'm ruining my brand new clutch.

Is this normal? Is it bad for my clutch? If it's abnormal what would cause it?

 

what is your warmed up idle RPM?

 

Idle Air Control (IAC) valve

 

Warmed up RPM is 750. But it doesn't get completely down to 750 until the Temp sensor reads right in the middle.

How sure are you it's the IAC? How hard is that to replace?

 

Pretty damn sure... I mean unless I see exactly what its doing in person Im not gonna make any promises. But pretty much the same thing happened to me on my old Ranger, it was the IAC. And from what I recall it took about 15 minutes to replace... that was a different engine though. Never done it on a 3.4

 

Did you have to replace it or were you able to clean it and fix it?

 

I just replaced it... I looked in my manual and it looks like it's on the underside of the throttle body on the 3.4. Gotta remove the throttle body then it's just 4 little bolts to remove it. If u have access to a manual, there are some testing procedures you should do before replacing it. Just to be sure ur not wasting ur money

 

I don't have the manual yet, the parts store didn't have it in stock:/ any chance you could explain the testing procedure?

 

Sounds like a vacuum leak.

 

Did yours also idle down to normal once your truck was completely warmed up? I just had it all apart, cleaned everything and reset the ECU and it still does it:/ looks like I might be buying the part

 

Generally what mine did was as soon as i started it would shoot up to about 2k rpm, then I would give it a little gas and it would drop down... but every once in a while it would stay high until warm. And it was a 5 speed manual trans too so I know how u feel there. lol

 

Yeah:/ it feels so bad shifting while it's doing this. Mine doesn't go down when I hit the gas ever, but it sounds like a pretty safe bet that I need to replace the IAC

 

I'm sure its your IAC as well. I cleaned my throttle body a while back without taking it off and I think I let some gunk drip into the IAC. Since then I have a really high idle when cold that lasts close to 20 minutes if I let it go that long.

 

Dang, I checked how much they cost at an auto parts store and it was over $200 and I already tried cleaning it. Might have to go the junk yard route

 

Mine doesn't idle high but once warmed up the idle drops to about 6oo rpm and it idles rough. Haven't thought it was necessary to check the IAC but maybe I should.

 

I wouldn't replace the IAC for a rough idle unless I was absolutely sure it was bad. There are so many other things that can fix a rough idle... Throttle body cleaning, spark plugs, plug wires, etc that are much cheaper and easier than the IAC