# Any guesses to an erratic idle when warm? [Video included]



## 200sxOuTKasT (Feb 24, 2003)

I got bored and decided to post a video of what my idle looks like after my car warms up (10-15 minutes of driving). I've recently replaced the the distributor cap and rotor, my spark plug wires and spark plugs, o2 sensor, radiator and its hoses, thermostat temp sender and sensor. I cleaned my IAA valve a while back but I'm hesistant to think this is the problem since it idles fine cold. If anything I'd appreciate any guesses to look at/replace that could effect the car's idle only when warm. 

Heres the video of what the idle looks like after my drive to the grocery store. I gave it a little gas at the beginning of the video so ignore that.
Idle test - 07-22-07_1427.3gp.swf @ ZippyVideos.com - Free Video Webhosting


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## trmn8r (Apr 16, 2005)

try pulling the the ecu and wait about half a day. so the the ecu can reset itself, the ecu has to relearn


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## Trippen (Feb 21, 2006)

Look around your injectors too for any signs of leaking..That looks like what mine did before i replaced my injectors. Either that or a small vacume leak


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## Ratrice (Jul 1, 2007)

Thats exactly what mine did when i had a vaccum leak. It would actually die at times, and not start back up for a few seconds. Good luck fixing it!


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## rogoman (Dec 16, 2004)

Check for a sticking EGR valve.


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## bristopathy (Jul 27, 2007)

I have a 98 Pathfinder that has a small vacuum leak causing the exact same problem. Engine idle stutters when engine warm. Check you air intake and if you have an evap emission system, try and determine if there are any leaks in it.


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## 200sxOuTKasT (Feb 24, 2003)

What's the best way to check for a vacuum leak? I've heard smoke machines but I don't think thats the cheapest and easiest thing to do... Also I heard with the EGR valve you could just tap it with a small hammer and it should effect the idle if the EGR is the cause no?


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## Trippen (Feb 21, 2006)

200sxOuTKasT said:


> What's the best way to check for a vacuum leak? I've heard smoke machines but I don't think thats the cheapest and easiest thing to do... Also I heard with the EGR valve you could just tap it with a small hammer and it should effect the idle if the EGR is the cause no?


The Vacuum leak you can do the Pressure test.. Is pressurize you intake manifold and listen for leaks..There is also the red neck way....Take a propane torch(the type you braze pipes with with a valve to open and close it) and* WITH OUT LIGHTING IT*) with the motor running open the valve on the Propane bottle a little and go all around the intake and vacuum lines...When the motor races or RPMs increases this is your vacuum leak. BE CAREFUL HAVE A FIRE EXTINGUISHER READY JUST IN CASE.


ERG can be found with the engine cool. You should be able to push the diaphram up and down..the part that moves can not bee seen from the top. Basically it is the whole bottom side that moves. If you do this hot you WILL BURN YOUR FINGERS. IF it does not move easily then it is toast or clogged..Sometimes you can take it out and clean it and it will work again. Or just block it off. Look on KA-t.org for information on what vaccume lines you need.

Check this out www.ka-t.org :: View topic - DIY Emissions Removal SOHC

OK the link is for the SOHC...There might be one on the DOHC side of the same sight.


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## rogoman (Dec 16, 2004)

200sxOuTKasT said:


> What's the best way to check for a vacuum leak? I've heard smoke machines but I don't think thats the cheapest and easiest thing to do...


To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. A good place to connect to is the charcoal canister. There should be three hoses connecting the carbon canister. Two of the hoses go to a purge valve that's built into the canister. The second larger hose off the purge valve should be your vacuum line. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be around 21 InHg.

If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.


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## 200sxOuTKasT (Feb 24, 2003)

Thanks Rogoman, I'm purchasing a vacuum gauge today to give it a try, as for the EGR valve though I tried pressing the diaphram when my engine was warm (used an insulated glove) and my car stuttered and almost died but that sounds normal. But I have no experience with EGR's to know whether its too stiff and needs to be replaced or is in good condition.


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## Trippen (Feb 21, 2006)

200sxOuTKasT said:


> Thanks Rogoman, I'm purchasing a vacuum gauge today to give it a try, as for the EGR valve though I tried pressing the diaphram when my engine was warm (used an insulated glove) and my car stuttered and almost died but that sounds normal. But I have no experience with EGR's to know whether its too stiff and needs to be replaced or is in good condition.



The car stuttering with the EGR pressed is normal at idle..the vacuum line pulls it up the higher the revs are to allow the exhaust to be recirculated into the intake. Simple device really.


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## GTRsilvia (Aug 16, 2007)

I had the same problem on mine at one time turns out all it was, was the spark plug wires had gone bad somehow.


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