[mustang1072]

with my rpms i normally idel a little under 1k well yesterday @ McDonald's drive through i was waitin 4 my food n my rps were bobbing back and forth between about 1000 and 1250... whats the deal? this is odd

[LanceD]

How long had you been driving at that point? Mine idles around there for a little while after I first start it, but after the engines warms a little it idles around 700 like its supposed to.

[GreenFaleen]

Do you have your tuner yet?

[mustang1072]

no but crazylegs said its on its way... needless 2 say i cant wait!

[GreenFaleen]

Hmm may have just been a fan shutting off or something mine did it every once in awhile before I got my tuner.

[mustang1072]

Originally Posted by LanceD How long had you been driving at that point? Mine idles around there for a little while after I first start it, but after the engines warms a little it idles around 700 like its supposed to.

one second it will b @ 1 the next second it will b @ 1250 and then it will go back down to 1 then back up to 1250 and it keeps repeating until i shut it off... im doin my best to explain this even tho its hard... ill try n get a sound clip sometime soon!

[GreenFaleen]

Thats weird, do you have a stick or an auto?

[mustang1072]

Originally Posted by GreenFaleen Hmm may have just been a fan shutting off or something mine did it every once in awhile before I got my tuner.

it has done it in the past but 2 b honest i just ignored it...that may of not been the best choice lol

[mustang1072]

Originally Posted by GreenFaleen Thats weird, do you have a stick or an auto?

stick

[GreenFaleen]

nm then. are you like sitting on the clutch and letting it out a bit to roll forward when it is doing it? You may just have the clutch at an awkward point.

[mustang1072]

no i just put the e-brake on and was sitting there listing to music (it was really busy haha)

[GreenFaleen]

hmm e-brake may have done it if you left it in gear.

[mustang1072]

i didnt hav it in gear cause it was on...lol

[GreenFaleen]

I figured not. I have no clue then man.

[tomzac]

Your idle is controlled by the IAC valve and the ecc. It's possible you just had a glitch condition in the ecc that caused this. Alternating rpms like that is an oscillation condition that can happen occationally, but it should not persist. Does it do it still? Have you changed something to you car or has the ambient temp changed abruptly? Do you use an oil/cotton air filter? Sometimes the adaptive learning portion of the ecc can develope a bad habit. If it persists, try clearing the adaptive learning by disconecting the battery from the car for 15 minutes or so. This clears the learned conditions and the ecc will start to relearn new ones.

[mustang1072]

Originally Posted by tomzac Your idle is controlled by the IAC valve and the ecc. It's possible you just had a glitch condition in the ecc that caused this. Alternating rpms like that is an oscillation condition that can happen occationally, but it should not persist. Does it do it still? Have you changed something to you car or has the ambient temp changed abruptly? Do you use an oil/cotton air filter? Sometimes the adaptive learning portion of the ecc can develope a bad habit. If it persists, try clearing the adaptive learning by disconecting the battery from the car for 15 minutes or so. This clears the learned conditions and the ecc will start to relearn new ones.

this is odd i kno but it does it alot after i drive 4 a while (lik 1 and a half to 2hrs) i use a BBk filter (cause thats my intake brand)

[tomzac]

Originally Posted by mustang1072 Originally Posted by tomzac Your idle is controlled by the IAC valve and the ecc. It's possible you just had a glitch condition in the ecc that caused this. Alternating rpms like that is an oscillation condition that can happen occationally, but it should not persist. Does it do it still? Have you changed something to you car or has the ambient temp changed abruptly? Do you use an oil/cotton air filter? Sometimes the adaptive learning portion of the ecc can develope a bad habit. If it persists, try clearing the adaptive learning by disconecting the battery from the car for 15 minutes or so. This clears the learned conditions and the ecc will start to relearn new ones. this is odd i kno but it does it alot after i drive 4 a while (lik 1 and a half to 2hrs) i use a BBk filter (cause thats my intake brand)

Did you install a cooler thermostat? You might have a vac leak, but unlikely. After a while a vac leak will throw a CEL code (check engine light). Some people say irratic idle can be caused by contaminates in the IAC valve. So you could try:

Cleaning the IAC valve (google search for how to)
Cleaning the MAF sensor with nonresidue electrical contact cleaner (google search for how to)
Check for vac leaks (including the CAI connections)
Clearing the adaptive learning (disconnect the bat for 15+ min.)

[Breakout]

Was your air conditioning on when you were sitting in the micky d's drive through? The compressor clutch engages/disengages constantly, causing rpms to sometimes flucuate....usually not that much though and usually not at that high of rpm.

[mustang1072]

Originally Posted by breakout831 Was your air conditioning on when you were sitting in the micky d's drive through? The compressor clutch engages/disengages constantly, causing rpms to sometimes flucuate....usually not that much though and usually not at that high of rpm.

no way! i wish haha i liv in iowa the weather was like -15 lol

[mustang1072]

Originally Posted by tomzac Originally Posted by mustang1072 Originally Posted by tomzac Your idle is controlled by the IAC valve and the ecc. It's possible you just had a glitch condition in the ecc that caused this. Alternating rpms like that is an oscillation condition that can happen occationally, but it should not persist. Does it do it still? Have you changed something to you car or has the ambient temp changed abruptly? Do you use an oil/cotton air filter? Sometimes the adaptive learning portion of the ecc can develope a bad habit. If it persists, try clearing the adaptive learning by disconecting the battery from the car for 15 minutes or so. This clears the learned conditions and the ecc will start to relearn new ones. this is odd i kno but it does it alot after i drive 4 a while (lik 1 and a half to 2hrs) i use a BBk filter (cause thats my intake brand) Did you install a cooler thermostat? You might have a vac leak, but unlikely. After a while a vac leak will throw a CEL code (check engine light). Some people say irratic idle can be caused by contaminates in the IAC valve. So you could try: Cleaning the IAC valve (google search for how to) Cleaning the MAF sensor with nonresidue electrical contact cleaner (google search for how to) Check for vac leaks (including the CAI connections) Clearing the adaptive learning (disconnect the bat for 15+ min.)

thanks man i will do all of thoes and let u kno how it goes!!