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Old 01-20-2010, 11:06 PM   #1
trbo_blu
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Join Date: Dec 2009
Location: Marysville, OH
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2007 Subaru WRX
WRB

Default 2007 WRX - Idle Air Control Valve?

I just picked up a 2007 WRX last week. The car does have 68K miles on it, but supposedly they are all highway miles. But anyways, at times during idle, it will drop down below 500 RPM and then surge up past 1200 or so RPM. It does it maybe once or twice a day randomly while sitting at a stop.

I did a search on idle issues and came across several posts recommending that the Idle Air Control Valve be taken off and cleaned as dirt and oil buildup can occur inside and cause idle issues. I was going to order a gasket to make sure I could replace it after taking off the valve.

However, I found a post which I can't find it now that someone had said the 07 didn't have a IACV. Its dark outside and I don't have a flashlight here at my apartment to go out and take a look to see if I see it or not. So my question is, was that a legitimate post or does the 07 WRX have a IACV?

If it does not, what other recommendations do you have? It hasn't thrown a code and doesn't do it that often. When does Subaru recommend a plug change? I thought about doing that this weekend while I am home because I'm sure they haven't been replaced yet and thought that might help. So to compound the thread, what spark plugs does everyone run in these cars? I'm accustomed to NGK in the past, but doesn't mean I have to use them. I run TR-6s in my GTO and haven't had any issues yet.

TIA!
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Old 01-21-2010, 04:59 AM   #2
CKxx
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Your BOV sounds lame
93 RX7+09 Forester

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If it is drive-by-wire, then there isn't one.
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Old 01-21-2010, 11:32 AM   #3
arghx7
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does the car have any mods?
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Old 01-21-2010, 05:12 PM   #4
trbo_blu
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Quote:
Originally Posted by arghx7 View Post
does the car have any mods?
No, it is completely stock. It did have an HKS blow-off valve on at for an unspecified amount of time (it came with the car).

And today I confirmed it is DBW and doesn't have an IACV...but still something is going on with the idling that I need to figure out. Its not something that is very frequent yet, but I'd still like to find the problem and fix it.
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Old 01-22-2010, 03:12 AM   #5
thunder_lizard_1976
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Cuz Chicks Dig The Wagon

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Try cleaning the Mass Airflow Sensor first (and make sure the plug contacts are tight), and if you're up to it, pull the I/C off, and clean the gunk off the throttle body/ plate as well. Do a reset, allow a few key cycles to do a relearn, and (hopefully) all should be well. Also check to make sure all your vacuum lines are intact/ secure, as that willl cause it to 'hunt' at idle as well.

As for the plugs, if the car is still stock, or even with minimal mods (intake, etc.), stick with the NGK's; There's no need to start mucking about with heat ranges/ materials until you get into heavier mods. I have found however with my own car, it does wonders for driveability to actually close the gap a few thousandths, iirc spec is .035, mine are set at .032. Because of the crappy stock tune, the 06-07's tend to literally 'blow out' the spark under high boost/ hard acceleration, and it seems to make cruising much smoother. The recommended interval is 60K; if you are daring enough to try and change them yourself, be especially wary of #4 (driver's side, rear)...I've been there, broke that, while trying to tighten it

Last edited by thunder_lizard_1976; 01-22-2010 at 07:19 AM.
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Old 03-25-2010, 09:41 PM   #6
IH8PVMNT
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2006 Wrx Limited BUG
2006 Wrx Limited Wagon

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Quote:
Originally Posted by trbo_blu View Post
I just picked up a 2007 WRX last week. The car does have 68K miles on it, but supposedly they are all highway miles. But anyways, at times during idle, it will drop down below 500 RPM and then surge up past 1200 or so RPM. It does it maybe once or twice a day randomly while sitting at a stop.

I did a search on idle issues and came across several posts recommending that the Idle Air Control Valve be taken off and cleaned as dirt and oil buildup can occur inside and cause idle issues. I was going to order a gasket to make sure I could replace it after taking off the valve.

However, I found a post which I can't find it now that someone had said the 07 didn't have a IACV. Its dark outside and I don't have a flashlight here at my apartment to go out and take a look to see if I see it or not. So my question is, was that a legitimate post or does the 07 WRX have a IACV?

If it does not, what other recommendations do you have? It hasn't thrown a code and doesn't do it that often. When does Subaru recommend a plug change? I thought about doing that this weekend while I am home because I'm sure they haven't been replaced yet and thought that might help. So to compound the thread, what spark plugs does everyone run in these cars? I'm accustomed to NGK in the past, but doesn't mean I have to use them. I run TR-6s in my GTO and haven't had any issues yet.

TIA!
haveing the same problem!!! surge in idle is drving me crazy, also have a 06 wrx.... did you find anything ?
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Old 03-25-2010, 09:51 PM   #7
fast06wrxtr
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Default

Quote:
Originally Posted by trbo_blu View Post
I just picked up a 2007 WRX last week. The car does have 68K miles on it, but supposedly they are all highway miles. But anyways, at times during idle, it will drop down below 500 RPM and then surge up past 1200 or so RPM. It does it maybe once or twice a day randomly while sitting at a stop.

I did a search on idle issues and came across several posts recommending that the Idle Air Control Valve be taken off and cleaned as dirt and oil buildup can occur inside and cause idle issues. I was going to order a gasket to make sure I could replace it after taking off the valve.

However, I found a post which I can't find it now that someone had said the 07 didn't have a IACV. Its dark outside and I don't have a flashlight here at my apartment to go out and take a look to see if I see it or not. So my question is, was that a legitimate post or does the 07 WRX have a IACV?

If it does not, what other recommendations do you have? It hasn't thrown a code and doesn't do it that often. When does Subaru recommend a plug change? I thought about doing that this weekend while I am home because I'm sure they haven't been replaced yet and thought that might help. So to compound the thread, what spark plugs does everyone run in these cars? I'm accustomed to NGK in the past, but doesn't mean I have to use them. I run TR-6s in my GTO and haven't had any issues yet.

TIA!
This sounds like what my car does after I reset the ECU. If the battery was pulled recently, it will do it for a hundred miles or so until the computer learns a bit.
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