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Old 08-20-2014, 09:12 PM   #1
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Idle issue

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So I bought a 99 gt 5spd, 103k miles
Not sure about engine modifications except for it definitely has a cai and exhaust work.

The car runs fine most of the time, however if the engine is warm, on start engine revs to around 11-12k, then drops to the point where it almost stalls - i would say around 4-500rpm. Sticks there for a couple of seconds and then finds a normal idle of around 800.
I feel like this may get worse and it may start stalling. Thoughts?


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Old 08-20-2014, 09:48 PM   #2
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Could be lots of things. How old are plugs and wires? Fuel filter...O2 sensors.
Mine had a real bad Idle problem and stalling. I was able to data log with my Toque app, wound up being a bad o2 sensor

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Old 08-21-2014, 10:02 AM   #3
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Good questions and I don't know the answers to any of those things. The guy I bought it from made himself out to be a mechanic of sorts and claimed to have done a full tune up on it recently, but I should probably pull a few plugs and see what they look like.
Thanks.

What is a toque app?


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Old 08-21-2014, 10:57 AM   #4
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[ QUOTE=Jdubbly;2070343]Good questions and I don't know the answers to any of those things. The guy I bought it from made himself out to be a mechanic of sorts and claimed to have done a full tune up on it recently, but I should probably pull a few plugs and see what they look like.
Thanks.

What is a toque app?


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Yeah my dealer was suppose to replace a good amount of things too... Don't trust that lol.



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Old 08-21-2014, 12:43 PM   #5
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Faulty IAC (idle air control) valve is a usual suspect. Also clean your MAF element and do a general tune up if you haven't already. At 103k you are due for new plugs and coils if its not documented in the maintenance that it was already done.
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Old 08-21-2014, 04:08 PM   #6
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Ok thanks scotty


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Old 08-21-2014, 05:31 PM   #7
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Originally Posted by V6 stang View Post
[ QUOTE=Jdubbly;2070343]Good questions and I don't know the answers to any of those things. The guy I bought it from made himself out to be a mechanic of sorts and claimed to have done a full tune up on it recently, but I should probably pull a few plugs and see what they look like.
Thanks.

What is a toque app?


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Yeah my dealer was suppose to replace a good amount of things too... Don't trust that lol.



Yes I edit my posts a lot, auto correct likes to sabotage me![/QUOTE]

If youre on Android search for our in the play store, full version is $5 that coupled with a $30 Bluetooth obd2 scanner and toy get real time info that you can data log and view a bunch of engine parameters and diagnostics.

I guess you could call it a ghetto version of an sct or other handheld tuner, that in the sense that with most of those you can change certain things like gear ratio and add custom tunes. Torque app just let's you view live data, plus got can save data, email it to yourself in excel format.

Worth the $35 I am in to it IMO.

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Old 08-21-2014, 06:07 PM   #8
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Ok cool thanks for the info. Is there an iPhone app that does the same thing? Forgive me in advance for not searching!


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Old 08-21-2014, 07:07 PM   #9
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I'm sure there is, I own nothing Apple though

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Old 08-21-2014, 08:12 PM   #10
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Quote:
Originally Posted by scottydsntknow View Post
Faulty IAC (idle air control) valve is a usual suspect. Also clean your MAF element and do a general tune up if you haven't already. At 103k you are due for new plugs and coils if its not documented in the maintenance that it was already done.

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Old 08-21-2014, 08:20 PM   #11
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Seems like I read something about cleaning the iac, good idea or just get a new one from ford?


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Old 08-21-2014, 08:28 PM   #12
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Seems like I read something about cleaning the iac, good idea or just get a new one from ford?


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If you take your IAC off, you will see a ton of carbon inside the actuator. Try cleaning it out with a fast drying none abrasive cleaner. Reinstall and see if that makes a difference with your droppng in rpms at a stop and start-up. You may want to go buy one, but I would exhaust all else first before just replacing parts. That tends to be expensive and aggrevating if the problem persists. Doing your normal tune-up procedures and cleaning of vital air intake parts most times can cure the problem. COP's do go bad also, but majority of the time when a COP is failing you would get a CEL showing a bank running lean or the like. But, take a look into your throttle body and see if it is all carboned up also, and clean it out. Spark plugs, COP boots dry rotted or cracked can cause spark interference. So just spend some valuable time loking your engine over and throughly inspect those intake parts. Let us know what you find or post some pics or a video of the RPM issue you are experiencing. That would help out alot.
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