Strange idle issue shutting off car sometimes

[Jarrod164]

So I'm not exactly sure how an IACV works. My friend puts doubt into my mind thinking it's only in use after driving the car but I know you all have issues with it on startup.
My car froze to near death in -40 or so weather on Monday and I didn't get it started. Went back the next day and dropped in a new battery. Had to crank it for 30 seconds and it eventually turned over. The gear shifting was tough... like I was shifting through molasses or something really crazy thick! Should I get different gear oil? (using Castrol 75w-90 I believe, non-synthetic).

Anywho, so all was well, then later that night I am driving on the freeway and clutch in to come to a near stop and the idle falls to 0 and shuts off the car.
This doesn't happen often at all, happened today so that makes it twice. But as I go into neutral, sometimes the idle will bounce between 900 and lower.

I never had an issue with my IACV before but this could be it. I remember some were saying don't clean it with brake cleaner or something as seals will be ruined. Just thought I'd throw this topic out there and gather opinions. It's not all the time, just random.

Thanks.

[Soren]

How's your MAF treating you? Have you cleaned it recently/inspected it?

[Jarrod164]

Never looked at it before. I've never had any issues with my car really.
And would a sea foaming give the IACV any cleaning?
Can you visually see the maf looking crappy? I'm sure I can do the whole re-solder the joints thing. I have a spare impreza so I'll do it to that one first and swap them perhaps.

[Soren]

Well, I ask because I've had a couple MAF's go, and I think the first thing was that you'd get an unexpected stall. When the maf gets worse, it just starts giving a strange idle and then eventually you won't be able to start it.

I think what I'd suggest is a good ole fashioned MAF cleaning. You said you have another, swap it in and see if it makes a difference. You are likely right with the IACV diagnosis, but cleaning the maf is easy!

EDIT - you will possibly see little balls of dirt etc in the maf.

[JDB]

Sound like a IACV issue or it could be a vacum hose that blew off or split. Either way it sounds like it related to manifold vacum to me.

[ElectricNipple]

It really couldn't hurt to pop off the MAF and check that, as that's probably the easiest solution. The IACV is also pretty easy to remove and clean, or even just remove and replace the gasket. My car idled at around 1800 rpm for a very long time until I removed my IACV, reinstalled with a new gasket and suddenly the idle was at a much healthier 1100, which makes me think they're just a pretty finicky part of the engine.

[jdmvip]

I guessed MAF right away just like Soren because they often go bad and stalling is a likely symptom.
Someone here made a thread on how to fix some MAF problems by resoldering.

[JDB]

Originally Posted by jdmvip

I guessed MAF right away just like Soren because they often go bad and stalling is a likely symptom.
Someone here made a thread on how to fix some MAF problems by resoldering.

Yeah, that was me. Here it is for reference.

http://forums.jdmvip.com/How_to_Fix_...56-t#post50883