ascMcLaren Enthusiasts

Havoc · Joined: 05 May 2008 Posts: 87 Location: Lebanon TN

I have been trying to pinpoint a nasty case of Idle surge when I'm at a stop. it comes and goes but its getting to a point that If I'm at a Stop the RPM's Jump then the car stalls. Runs just fine while driving and there are days I dont have the issue but as of late it seems to be worse.

Any Ideas ? Could it be the IAC sensor going bad?
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1986 White vert McLaren# 196

Sandy · Posted: Mon Sep 15, 2008 12:33 pm Post subject:

??? 4 U

Could it be the EFI going bad ??
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Sandy passed away in 2012. He will be forever missed.

1990 Final Car prior to the 12 Silver Anny Editions
1990 Silver Pearl Anny Edition
1986 Coupe Full Pkg #109 of 114.

http://public.fotki.com/ascmclaren/ascmclaren_capris/sandys_mclarens/

trvlnmann · Joined: 23 May 2006 Posts: 113

I would start by running the diagnostic codes. If you have never done it before it's easy to do. See what codes come up and go from there.

The IAC is a possibility, as is TPS, vacuum, EGR and so on.

86capriasc · Joined: 12 Nov 2005 Posts: 377 Location: wisconsin

Check out this site, you will have no problems figuring out your problem. Joel is a wiz, and great info from everyone over there.

http://sbftech.com/index.php?board=20.0

Mike
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1986 ASCMclaren #108
stock E7 short block, explorer intake, 65mm TB, home built Gt45 turbo kit, 3.08s, Borla cat-back, '05 slot maf, Gt-40p heads, TFS1 cam, 80lb injectors, E85, Qaurterhorse tuner.

Havoc · Joined: 05 May 2008 Posts: 87 Location: Lebanon TN

wow I hope it isnt the EFI, I get to a stop and it idles rough and stalls at times. I'm hoping cleaning up the throttle body will help. Thanks for the site I will check it out.
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1986 White vert McLaren# 196

mandra · Posted: Tue Sep 16, 2008 2:13 am Post subject:

Also check hard for vacuum leaks. They are a common cause on these old dogs.

xbgt · Joined: 10 Aug 2007 Posts: 43 Location: Milton, FL

I can tell you exactly what it is, the Idle Air Flow Control. It sorta looks like a minature fuel pump, it will be up near the throttle body. They go wacky at times. Just swap a new one on and she will be happy again. You can probably grab one at any Upull it place as well. And, I have found one off a 2.3 works just the same. I had an Aerostar van with a 3.0 in it, it wanted one per year and also an Explorer, about every 18 months, not sure why. Anyhow, it just an 8mm socket and one snap on plug, can change this is less than 5 mins.

Hope that helps,
Chris
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1985 GPIV
1986 ASC Vert
1986 Eurocoupe #13
a few Capri's
Aussie Ford's
www.LastV8.com

Chris · Joined: 22 Aug 2005 Posts: 17 Location: San Diego, CA

I had the same problem with my other mustang surging at every red light. It turned out to be a vacuum leak and man was it a pain to pin point. All of the suggestions mentioned above are dead on. Start by running your codes.

Havoc · Joined: 05 May 2008 Posts: 87 Location: Lebanon TN

UPDATE!!!! I took off the IAC and cleaned it with some MAF cleaner and got a new TPS sensor at Advanced for 39.99 and she is running better than ever. Thanks for the Help Smile

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1986 White vert McLaren# 196

xbgt · Joined: 10 Aug 2007 Posts: 43 Location: Milton, FL