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Idle issues after head gasket replacement

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So I got my car back on Tuesday after getting the head gasket replaced. I also had the inlet manifold gasket and exhaust manifold gasket replaced.

My issue now is everytime I start my car up, it'll idle around 1200-1500 for a min, then drop down and fluctuate between 550ish-1100ish. At first I thought it might have something to do with the Power FC and the idle search mode that it has. After following the guide I've found online (letting car idle for 10 min, then turn on the rear defroster for 10 min, then the AC for 10 min), the car idled perfectly around 1000rpms. I figured problem solved. But the idle fluctuates everytime I start my car up after it's been sitting for a while. It'll fluctuate about 15-20 min (if I have the time to let it sit) before settling down. After the car is fully warmed up, the idle issue is gone.

I've read online that it could have something to do with AFM, but my mechanic says when he took a look at it, it looked good. He's got me booked for Monday morning for a free service, but I was wondering if anyone had any suggestions on what my issue could be. I know I need to get the car mapped, but I've never had this issue before the gasket change, and wouldn't think that it would cause an issue like this. But I'm not a mechanic, so I don't know for sure.

Any advice would be appreciated.
 

S15_SAM

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You can't look at an Afm and see it looks alright, it needs to be tested with a multi meter to check the voltage readings.

You can map idle adjustment so could be that. AFM is most common for idle issues, check sxoc they have a few 2nd hand. Otherwise you are looking at an air leak or idle control valve issue.
 
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Not sure what he meant by looked at. He could have checked it with a meter or not. I'm sure if he hasn't, he will check it out on Monday. Thanks.
 
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When I get home tonight, I plan on taking a look at those parts you guys suggested. I took a quick peak during lunch and I was able to locate the AAC and the BOV, but I wasn't able to find the MAF (or AFM). I'll have to try and take a deeper look tonight.

If needed, I'll try and clean them up a little.
 

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The MAF is just after the air filter it had 3/4 wires and a plug, plugged into a little black electric pack. Not a lot you can do with it, some say its ok to clean with electrical cleaners but I don't like it and would buy a new one or quality 2nd hand
 

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take it your rad was emptied ? few lads with sr's have problems incl myself with weird idling due to airlocks after refilling the rad.
 
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I don't see the MAF after the air filter. I'll give it a better loom tomorrow. I'm sure it's just sitting there in front of my face.

As far as the rad, yes it was drained. If there are air locks, will they eventually work their way out?

its strange that after about 15 min, it idles perfectly, but if I let the motor cool down, it'll do it again. Really hope this turns out to be a simple fix.
 
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its strange that after about 15 min, it idles perfectly, but if I let the motor cool down, it'll do it again. Really hope this turns out to be a simple fix.
Just check your coolant levels, the cold start on the throttle body runs off your engine coolant as well. Might be worth backing it off to check if thats the problem. Your O2 sensor can also cause idle issues
 
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The coolant level is spot on. Hasn't dropped since getting the car back from the shop.

I took off the ACC and it was pretty dirty, actually really dirty. I cleaned it up with some intake/carb cleaner. Would it be a wise idea to try and clean out the throttle body and intake manifold? Can I do it without removing them?
 
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No to clean them properly you should remove them. Don't get any cleaner on the special paint on the edges of the butterfly valve as it is there to stop it sticking and you'll only srub it off. I put cleaner on a rag and wiped the throttle body. The plenum, just take the top half off to clean it.
 
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I cleaned as much as I could with a cloth. Put the ACC back on and started the motor. It was idling a little higher than usual. I adjusted the idle screw a little and got it to idle down. It seemed to be running perfectly. I let it warm up the. I drove it into the garage. As soon as I stopped, my idling problem came back, although it only did it for about 30 sec then idled normally. I turned the car off for a while and went in the house for a drink. About 10 min later I started up the car and the idle started surging again. Not sure what the issue is. Hopefully the mechanic can figure it out tomorrow.

Its gotta be something not connected or a leaking hose somewhere. The car never had this issue before the head gasket change.
 
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Might be a long shot, but check your throttle body gasket. I had an idle issue and it turned out to be a split in the gasket which was upsetting the idle control by sucking in unmeasured air. Have you checked your TPS as well
 
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Just got back from the mechanic. We found a small crack in my exhaust manifold. Fortunately it looks as if I'll be able to remove without too much trouble. Now I just gotta find a place that can weld it. My mechanic says he knows a few places.
 
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I've been searching online to see if anyone else has bad issues with idle surging caused by a cracked manifold. So far I haven't found anything to support it. The only thing I did find was an Eagle Talon forum where someone posted a similar question. One of the replies says that it's highly unlikely that a cracked exhaust manifold would cause this.

Im not trying to discredit my mechanic, but I'd like to be able to figure out what the cause of my idle surging is. The car ran perfect before the head gasket change. Now I've got this idle issue. Of course my next plan of action is to replace the exhaust manifold (welding it seems to be a waste of money as I've been quoted ridiculous prices that aren't much lower then just buying a new manifold, plus the weld might crack again). I just hate not knowing why my car is running like sh*t and possibly wasting money trying to get it fixed.
 
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No I haven't, but I did disconnect the aac valve plug and the car dropped it's idle to around 650-750, but wasn't surging as bad as when it was plugged in. Perhaps I need to try a new aac valve?

*edit*
I'm curious to know what the Power FC may have to do with my idle issue. Would I still be working on troubleshooting the IACV-AAC valve and TPS, or could it have something to do with a setting in the Power FC? I'm new to all of this, but am willing to go through some growing pains to learn.
 
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You might need to get the tune checked and your cold start and idle setup. Your mechanic hasn't been f***ing with the hand controller and accidently set it back to default settings
 
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I don't think he reset the hand controller. From what I can remember, the settings look the same as before.

But yes, I do need to get it tuned as soon as I can get the money for it.
 
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