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Idle/Stalling issues on 95 GT

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Idle/Stalling issues on 95 GT

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Old 04-05-2012, 04:40 PM
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kay15ace
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Default Idle/Stalling issues on 95 GT

My car is having issues staying at a consistent idle and stalling. When I first start it to let the motor warm up my car will idle around 750-900 rpms, and then when I drive it around a little and come to a complete stop with the breaks and clutch both pushed down my car will go down to that rpm range and then it will have a brief idle surge to around 950-1050 and then it will cut off, if I don't hit the gas and even if I hit the gas once it will still cut off so sometimes I have to keep my foot lightly on the gas. If my car doesn't cut off it will idle around 550-600 rpms. And this cycle continues for as long as I drive it. I tried adjusting the IAC to where more air comes in and my rpms didn't go up or down when I tightened the screw. Does anybody have any inputs?
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Old 04-06-2012, 09:49 AM
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#1 clean the throttle body, even though Ford has a sticker to NOT Clean it. there are a multitude of cleaners specificaly to do it from extensive kits to a bottle brush and throttle body cleaner, here is what needs to be done and why.

First the WHY:
through time even and especially with a fuel injected engine you almost always have some fuel vapor left over in the combustion chambers or on the back side of the intake valves when you shut the engine down. this fuel evaporates and dissolves the build-up in the intake manifold and in the vapor state builds up on the back side of the Throttle body plate. (Also oil vapor from the engine PCV system especially on a high mileage engine)

In the late 80's Ford started coating the throttle bodies with a coating that "Resists" this buildup but it still happens. The reason Ford placed the sticker to NOT clean it is due to the fact that the cleaners and brushes used to clear the TB will remove this coating which will change the idle of your engine and the buildup will occur more quickly. after the cleaning you should both re time the engine and reset the base idle AND Pull the Battery cables for about 20 minutes so that the computer will reset.

Basically here is the procedure:
1) Disconnect the air inlet to the throttle body and the battery negative cable
2) hold open or have someone hold the throttle plate at the fully open position (either by holding the throttle pedal to the floor or the linkage on the TB.
3) using a quality Oxygen sensor safe cleaner and a bottle brush or tooth brush (Nylon not brass or stainless) spray the throttle body and scrub the TB and Throttle plate to remove all varnish and buildup. Wipe it with a cloth rag not paper or you will get some small pieces in the intake that may or may not just burn through the engine.
4) repeat the process until you do not feel the buildup there. (you can also do this on a bench if you want to take the throttle body off the car so you can visually check the cleanliness of the work you are doing)
5) Reconnect the air inlet hose.
6) reconnect the battery
7) start the engine and let it warm up. (It probably will idle high, and don't worry about this yet.
8) once warm shut down the engine and remove the spout connector (by the air cleaner/filter housing) and reset the timing to factory spec.
9) connect the spout connector plug and unplug the IAC motor on the throttle body.
10) adjust the base idle to the spec on the engine decal setting for base idle (usualy 600-650 RPM)
11) reconnect the IAC motor plug.
12) let the car idle for a few minutes and it should level out.
13) go for a road test at least 10-15 minutes or longer
14) shut down the car and let it cool down.
15) go on another road test starting from a cold engine.

Your all done.

Since this is my first post i will give a little info on my Qualifications:
Worked for Ford as a Drive-ability and power-train engineer for 6 years starting in the mid 80's. Yes Engineer not technician. Have over 15 years experience with Ford EEC servicing and diagnostics. I can guarantee that if it has broken on a Ford i have fixed it.

Hope this helps,
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Old 04-06-2012, 01:56 PM
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brittny881
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I keep my IAC unplugged.

Usually with my IAC plugged up, it will rev high and quite often stall. Throttle body was cleaned and IAC replaced. I didn't like the way the IAC made the car rev between shifting so it's unplugged and the car runs so much better

If it were mine, I'd try unplugging the IAC, cranking it, and seeing if the problem still exists. It could be a faulty IAC too.

Experience: Nothing professional.. just trial and error on my 95
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Old 04-08-2012, 05:49 PM
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Venomantidote95
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I`ve never seen a car run and idle without an IAC unless it was speed density just sayin!
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Old 04-09-2012, 12:16 PM
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brittny881
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Originally Posted by Venomantidote95 View Post
I`ve never seen a car run and idle without an IAC unless it was speed density just sayin!
She's pretty much a stock cobra.. the idle had to be adjusted slightly because after IAC was unplugged she ran about 800RPM instead of the 950-1000 like I'd prefer. If it's a stretch to believe, I'll be glad to make a video to prove myself.
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Old 04-09-2012, 05:02 PM
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No thats ok i didnt say impossible!? I only said i havent seen one do it. Adjusting the throttle stop opens the flap enough to run the car instead of the iac metering it, that is prolly what you have done?

Almost every mustang i have unplugged the iac on dies immediately exept 1 SD car as i have previously stated.
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Old 04-09-2012, 05:39 PM
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She didn't stall the first time it was unplugged so my guess is as good as yours on it.

OP.. did you get your problem fixed?
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Old 04-10-2012, 01:31 PM
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Originally Posted by brittny881 View Post
She's pretty much a stock cobra.. the idle had to be adjusted slightly because after IAC was unplugged she ran about 800RPM instead of the 950-1000 like I'd prefer. If it's a stretch to believe, I'll be glad to make a video to prove myself.
You trying to use the base idle throttle adjustment for Cruise Control?
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Old 04-10-2012, 07:55 PM
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I keep my IAC unplugged.
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Old 04-11-2012, 08:47 PM
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No, it's not for Cruise Control.
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