As of late, I've been dealing with an issue where if I'm in drive and standing still, the idle sometimes surges. Nothing major, but the tach fluctuates by around 300rpm up and down, when it does. The other day I pulled up in my driveway after a 30min drive and the truck actually stalled. I restarted it and it seemed stable immediately after. No codes.

Anyway, I've never cleaned the IAC valve on this truck. On the 4.7, (facing truck) it sits off on the right side underneath the air hat. Seems like I should be able to remove it without even removing the air hat. I've read where some of these things stick when people try to pull them out. At 250K, that's probably my fate. Plan to clean it with a toothbrush and some carb spray. Anything else I need to be aware of?

 

It would be worthwhile to remove the air hat and look down into the throttle bore to see if it needs a good cleaning as well. Likely if the IAC is dirty the port to the IAC is dirty as well along with the throttle chamber. Be careful removing and reinserting the IAC as the pintle is fairly fragile, spray and scrub it down well and see if it helps your issue and report back. Good luck!

 

Absolutely remove the air box and take the throttle body off for a good cleaning. I just remove the 3 screws and leave the cables attached... cleaning the TB there under the hood. The IAC has two screws holding it to the TB. It's not so easy to clean inside the TB, but give a good go of it.

Many videos on cleaning the TB, but none talk about taking it off, sad. Use this link as a guide for cleaning.

 

I cleaned the TB at 246K, back when I did the plugs. I didn't pull it off though. Just stuck some rags down the throat and cleaned it. I'll go ahead and pull it off. Once I remove the IAC screws, how hard will it be to pull out? Yes, I'm afraid of damaging that pintle. Do you guys replace the TB gasket or reuse?

 

The IAC is easy to pull out, it will be loose when you remove the screws. Just pull it out straight and you are good. I would replace the TB gasket, it is only a $3 part at you local parts store.

 

Thanks, guys.

 

I usually replace the gasket because it's so cheap. But if it's in good condition I'm sure they can usually be reused.

And +1 for removing the TB. I like to give it good spay and soak with TB cleaner then hit it with a wire brush and give it another good spray.

 

Yup, you're going to wipe inside the manifold where the old spray went (like I did).

 

Okay, so months later, I finally cleaned the IAC valve. A few days ago, the truck was stalling or near stalling whenever I stopped.

The valve didn't look like the typical ones I saw. It is secured to the TB with a single torx screw and had two O-rings when I removed it. There was no plunger, or point to it... rather, it was a cylinder with a hole in it (forgot to take a pic). I doused it with carb cleaner, cleaned a with a toothbrush and reinstalled. In my impatience, I may have put it back a little wet. Anyway, I took it for a drive and the idle was surging up and down when at a complete stop. Watching the Tach needle, it would rise and fall from 5K to 9K, cycling every few seconds. Either I have a bad IAC, or it needs to dry out a bit more. I'll see how it runs in the AM.

Edit: Valve looks like this...



Locating IAC valve...

 

As far as I know you are NOT yes NOT supposed to spray it with cleaner or carb cleaner it will damage it. You spray the chamber and only wipe the IAC off with a cleaner no spraying it.