Hi All,

So I have an issue where when I've been running my 4Runner for a while, usually 45 mins + I will VERY occasionally stall at idle.

Here is the list of thing's I've done.

- New plugs/wires (not coils)
- Cleaned throttle body and ICV
- New Valve Cover Gaskets
- Cleaned MAF
- New fuel filter
- Checked Air Filter - did deckplate mod
- Removed slack from throttle cable and transmission cable

I don't see any obvious vacuum leaks, but having done the valve cover gaskets, I pretty much a lot of it unhooked and gave everything a once over, but I've not done anything comprehensive either.

Not getting any codes or anything. Otherwise, the truck runs like a champion, and even when it stalls, it starts right up and runs fine, so this is only a very mild annoyance.

Only happens when the truck is really good and hot. Never when cold. Only other thing I can think of is to start swapping out sensors. Looking for any suggestions/ideas.

Classic IAC valve failure. I know people like to clean their throttle bodies, but honestly the majority of the time the IAC starts sticking is right after the throttle body has been cleaned. There's two holes at the bottom of the throttle body, one before the butterfly valve and one after. If gunk is pushed in to either of these it starts sticking and causes the engine to stall out only when hot.

Best bet it to remove the throttle body completely, remove the IAC valve from the bottom and blast it out with carb cleaner and hope that does the trick. You can try to manually move the valve open and closed with a small screwdriver and if it sticks, apply the smallest amount of oil to free it up.

If you want to also check for vacuum leaks, this is the best way to do it and only takes a few minutes:

So the stalling issue pre-dated my cleaning of the throttle body. And predated my replacement of the valve cover gaskets. I removed the IAC during the valve cover process and went to town on both the throttle body and the IAC - it's possible that it got more gunk in it somehow but I was pretty thorough on the cleaning - and since the same problem existed before... you might be right and it may just be time to replace the IAC.

Thanks!

you can just remove the IAC coil exposing the armature and it should rotate freely, I set mine at a perfect idle and dabbed a little epoxy to keep it in place. I couldn't tell any difference, leave the coil plugged in but unattached and it won't throw a code.

Ah, yeah that'd be the most likely cause. IAC valves are pricey though, maybe try a junkyard.

Worth testing for vacuum leaks first, it's free and a new IAC valve costs over $200.

There’s not a lot going on with an IAC valve. Has anyone tried to rebuild one?

I think you would be the first! If it's not a daily driver that you depend on, worth a shot. If you do and it's successful, post a few photos of what you did & start a new thread. It would be a great help to a lot of the members on here.