Idling high when in neutral and coming to a stop??

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Idling high when in neutral and coming to a stop??

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Mustang Forum >> Ford Mustang Tech >> 2005 - 2008 Mustangs >> 4.0L V6 Specific >> Idling high when in neutral and coming to a stop??

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Idling high when in neutral and coming to a stop?? - 5/1/2008 11:58:00 AM

kevinmalec

Posts: 77
Joined: 4/7/2008
From: Acworth, GA
Status: offline

I've been experiencing high idle issues for about 2 weeks now. It occurs when I am slowing down to a red light or stop sign. Once I come to a complete stop, the car is still idling around 1.5 RPM! After a few seconds the idle will go back to normal....It used to do it everyonce in awhile; however now it is occuring all the time. It's a good thing I have a 5 speed and am able to put it in neutral. If I had a manual, I think it would pull me forward and would be hard to stop!

Any ideas on what maybe causing this issue?

Suggestions/ideas?

Thanks!

_____________________________

- 2005 V6
- 5 speed
- Airaid CAI
- Single Pypes Street Pro Exhaust
- 20" Cobra Rims
- 235/55 R20 Sumitomo HRTZIII
- Chrome honey comb grille

Post #: 1

RE: Idling high when in neutral and coming to a stop?? - 5/1/2008 12:28:23 PM

billybix76

Posts: 252
Joined: 12/18/2006
From: Boise, Idaho
Status: offline

Pretty common. Mine does the same depending on tune. According to my engineering source at Ford, should only happen while coasting in neutral. its intentional as the ECM needs to keep up oxygen sensor temp to keep the emissions within spec. They accomplish this by revving idle up to 2K rpm while coasting in neutral with the clutch out on manuals. It is road speed sensitive, it will throttle down when ECM senses cluth down coasting, or at a stop. I dont know if Auto's have this issue (unless they put it in neutral while coasting?) . The only cure I know of is to get a tune from Justin at VMP that turns off the downstream rear oxy sensors and he can then tune it out. I think Doug does this as well for his tunes...

< Message edited by billybix76 -- 5/1/2008 12:32:19 PM >

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(in reply to kevinmalec)

Post #: 2

RE: Idling high when in neutral and coming to a stop?? - 5/1/2008 12:54:04 PM

kevinmalec

Posts: 77
Joined: 4/7/2008
From: Acworth, GA
Status: offline

I appreciate your feedback billybix. :)

I've purchased my stang over a year ago and the high idle just started about 2 weeks ago. At this time, the only modification I have is the single Pypes Street Pro Exhaust, which I installed about 5 months ago. I have my Airaid CAI in route and will be delivered tomorrow.

Has your car been experiencing the high ilde issues since you got it?

I've been doing some research here on the forum and some people say it maybe the IAC or a vaccuum leak??? I am not very mechanically enclined and am not sure where to look for these.

Thanks again for your response!

_____________________________

- 2005 V6
- 5 speed
- Airaid CAI
- Single Pypes Street Pro Exhaust
- 20" Cobra Rims
- 235/55 R20 Sumitomo HRTZIII
- Chrome honey comb grille

(in reply to billybix76)

Post #: 3

RE: Idling high when in neutral and coming to a stop?? - 5/1/2008 1:27:31 PM

Wishbone

Posts: 99
Joined: 3/23/2008
Status: offline

I had the same problem on my '01 GT. There was a simple fix for it that fixed it right up. Maybe this will work on yours?

http://www.mustangforums.com/m_2625353/tm.htm

(in reply to kevinmalec)

Post #: 4

RE: Idling high when in neutral and coming to a stop?? - 5/1/2008 2:34:35 PM

vtmustangs

Posts: 456
Joined: 2/7/2008
Status: online

I have had that problem too when you just engage the clutch again it goes back down it if bothers you

(in reply to Wishbone)

Post #: 5

RE: Idling high when in neutral and coming to a stop?? - 5/1/2008 4:19:25 PM

SkullE404

Posts: 53
Joined: 2/15/2007
Status: offline

Believe it or not (this happened to me) the gas pedal and brake are unusualy close in the mustang and when you are braking the "side" of your foot is pressing the gas pedal.

Now whenever i get a high idle i move my brake foot and it slows down.

_____________________________

2006 V6- 5 Speed

(in reply to vtmustangs)

Post #: 6