idle probs

Discussion in 'SN95 V6 Mustang Tech' started by ryanrule, Nov 25, 2003.


  1. ryanrule

    ryanrule impotent Founding Member

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    my car would not idle at all this morning, i had to keep on the gas the whole time, does this often when its cold out, any ideas?
  2. '03 6-Speed

    '03 6-Speed New Member

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    You may need to adjust the little screw thats on the throttle body to increase default air and fuel flow, but I tried that once and my ECM got a little upset, but I had to change it since I installed a Throttle Body Spacer. But I would possibly adjust that screw to increase your default air flow and see how that does.
  3. ryanrule

    ryanrule impotent Founding Member

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    any idea while its only when its cold and only seldom then?
  4. 98v6mustang

    98v6mustang Founding Member

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    maybe the cold air temp sensor?
  5. 97v6Silver

    97v6Silver it came to $4.56 and i got $0.44 change from a 5,

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    when it's cold the oils not warmed up and causes more friction and where everythings more cold/dence there more compression and it may cut off at low idle... this is jsut my theory... just a cold weather thing needs higher idle to fix..
  6. ryanrule

    ryanrule impotent Founding Member

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    it doesnt happen all the time though, just like the first time it gets cold, and whnever we have a wet snow
  7. 98CobraClone

    98CobraClone New Member

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    is your IAC (idle air control) sensor clogged up (oily)? you may wanna take it off, and check it to make sure it's not gummed up and clogged. You can use the wal-mart or autozone brand of carb cleaner to clean it up good as new, should help 100%
  8. DanM

    DanM Founding Member

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    Bingo.

    99.9999999% of the time a low or stumbling idle is fixed by doing the following:

    -Pull off and clean your IAC. Make sure the electrical connectors are okay (although if they weren't you'd be getting a SES). It's likely just the mechanical valve sticking when cold, so inspect it, clean it with some carb cleaner, and if necessary, replace it with a new one.

    -Remove and clean your TB. Gunk can build up around the butterfly thanks to those wonderful PCV and EGR systems. Clean all that goop out, and make sure the butterfly moves smoothly. Be careful around the TPS - those pot.s break easily.

    -Speaking of TPS, inspect the electrical connectors there, although, as with #1, if that were the issue, you'd have a SES.

    -Toss in a bottle of injector cleaner on your next tank for good measure.

    -If you haven't done it in a while, now may be a good time to replace the fuel filter. A lot of people assume bad idle is caused by no air, and forget all about fuel. A clogged filter can kill your idle, so make sure it's flowing freely, and replace it if it's not.

    Do all those and I promise your issue will go away. Unless you're that unlucky 0.0000001%. :)
  9. '03 6-Speed

    '03 6-Speed New Member

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    Where exactly is the IAC, I think I may do this myself.
  10. SpectorV

    SpectorV Founding Member

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    mine did the same exact thing, its the idle bypass valve... they get stuck especially when its cold, its a simple fix, its located on the upper intake on teh back side by the firewall near the throttel body, cylinder shaped.
  11. SpectorV

    SpectorV Founding Member

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    and they are dangerous in manuals and possibly in autos also. any time you are in neutral the car can go dead if they dotn work right (idle bypass valve) i was coasting around a corner to my house and my car went dead, no power steering, if there was a car comming i may have been killed.
  12. DanM

    DanM Founding Member

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    [QUOTE='03 6-Speed]Where exactly is the IAC, I think I may do this myself.[/QUOTE]
    As you're standing facing the car, looking into the open hood, you'll see the big black air intake tube on the left. The tube meets up with the throttle body, which is attached to the upper intake manifold. If you look at the top of the throttle body/intake crossover, you can see a little passage that runs along the top of the TB and down around behind the intake crossover tube. That's the IAC passage. On the back of the intake crossover, behind the throttle body, you'll see a small unit attached with a cylindrical solenoid valve. That's the IAC valve that opens and closes to let air through that passage when you have your foot off the gas. Basically - pull that apart, inspect and clean it.
  13. ryanrule

    ryanrule impotent Founding Member

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    what should i be lookin for?
  14. SpectorV

    SpectorV Founding Member

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    the IAC or idle bypass valve is on the upper intake, its between teh throttle body and the firewall, on 99 up, its round cylinder shaped on all years and has to be close to the throttle body you cant miss it, its the only round cylinder shape thing around the throttle body.
  15. ryanrule

    ryanrule impotent Founding Member

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    i know where it is, i took it off and inspected it. i was wondering what to look for in problems
  16. DanM

    DanM Founding Member

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    Nothing in particular really - just anything "abnormal". Make sure it's not caked with gunk, not sticky, damaged, wet (leaky)... whatever. Sorry I can't be more specific, but there isn't really one specific detail you're looking for. Just clean it, and if it seems to be okay, it probably is...
  17. ryanrule

    ryanrule impotent Founding Member

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    no prob with it , it was just cold from bein outside
  18. 97v6Silver

    97v6Silver it came to $4.56 and i got $0.44 change from a 5,

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    get a electric heater... have the little cable hanging out...

    you could tell your friends "yup swapped in a 8.6L turbo Diesal, 200 hp and 1,564 ft/lbs... it can tow a skyscraper at 40 mph..."
  19. 98CobraClone

    98CobraClone New Member

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    you may be able to just clean it up with carb cleaner (spray) for any parts place. When I did that, I just waited for it to dry up, tried moving the spring inside, put a little oil on it, moved it a little more and put it back.

    No more idle probs
  20. DanM

    DanM Founding Member

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    Exactly. Just clean it, lube it, put it back together, and go. Either your problem will go away, or that wasn't the problem to begin with. Unless there was a major failure, you won't really 'see' anything glaringly wrong with the IAC. Just revitalize it a bit and go.

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