Doing some maintenance on my 99 5vz-fe. My truck has a bit of a shudder at idle, and has come pretty close to stalling a couple times. If I stay on the throttle, there are no problems. The severe shuddering doesn't happen ALL the time, but there is at least a minor shudder all the time.

I think the IACV is the issue. I haven't yet inspected it, but I think I'm just going to replace it proactively. I'll clean out the throttle body as well. I'm also going to be replacing the PCV.

I plan on goin OEM for the pcv, but I haven't been able to figure out if the dealer sells the IACV or how much they are, and I don't want to be spending a ton of money.

My question is, is it safe to go aftermarket with the IACV? Any recommendations on brands? I found a few online, but I don't want to pull the trigger on an aftermarket until I know its safe.

You could start by removing the vacuum line on the side of it and spraying a good carb cleaner or throttle body cleaner in that hose connection and see what comes out the IAC inlet hole in the throttle body. If it’s dirty coming out keep going till it’s clean.


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OEM will be around $210+ for a new IAC. As long as yours is in working spec per the FSM, just take it off the throttle body and clean it well. Be gentle with the brass screws. Make sure to have a new gasket in hand.

But stay away from aftermarket ones. Very far away.....

Toyota IAC valves are different from most others, and are prone to sticking. Take it off and clean it and the throttle body. If that doesn't work replace it. The only IAC I've ever had to replace on a 5VZ engine is my own 4Runner because it just would not control my idle. I cleaned it, that didn't work. I tested the circuit and it checked out, so I replaced it with an aftermarket one from the local parts store and haven't had any problems since.

Have you had a bad experience with an aftermarket one? or read about it (links?) ?

Not personally but a friend did. He bought a $40 Amazon one and after trying everything else to get the idle back to 700 (it never idled down past 815 with the aftermarket one), he cleaned his old one, put it all back together with a new gasket, and it ran fine for another two years until his sis totaled his 4Runner.

Clean the throttle body as well.

I had the coil go bad on mine, removed the coil and the armature acts as a Idle adjustment. a dab of epoxy and idle was perfect.....but I had already ordered an aftermarket one so I went ahead and replaced it, I swear I can't tell the difference between the two set-ups? the aftermarket one was $50.

I'm going to disagree with you LilCaes, respectively of course. Im the first one to say OEM all the way, but I replaced mine with an ebay unit about 4 years ago and all is well. I'm not necessarily saying go that route, but I will say not all aftermarket IAC's are created equal. I think I paid $27 for it, and it was worth the gamble to me at the time based on the OEM price.

I guess what I am saying is that with the OEM one you are taking zero risk in trying to clean it, where as with an aftermarket one, it is a financial crapshoot.

With my friend’s aftermarket one we were assuming the valve was not set to the correct parameters to open and close, thus the high idle at operating temp. I asked him if he wanted to mess with it, maybe to try and set it to idle correctly. He said no and we sent it on it’s way to the landfill.

So, I was in the process of getting to my throttle body, and noticed what seems to be oil around one of the vacuum hoses connected to the port on the air hose closes to the throttle body (see picture #1 & #2). There was also oil build up inside the opening of the air hose closest to the throttle body (picture #3).

What would cause this?

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That is the fresh air vent for the PCV system.

If you have oil there you got more blow by than your PCV valve can take away at higher throttle settings when vacuum is low.

Either way it’s pushing up under pressure from the drivers side valve cover.




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Ill be replacing the pcv next week, is that the remedy?

It is a good start. Use OEM only.

Absolutely. Thanks!

so whats the part # for the gasket for the idle control valve