Ok guys.. need help with this one.. my idle changes randomly for no reason that I can see.. bascialy once i warm it up it ildes where it should.. around 750rpm.. but then i start driving and sometimes it will go up to around 900rpm.. and then if i drive and stop at another red light it may go back to 750 or might go up to 1k! its frustrating cuz it was idling just fine before I reset the ecu about two weeks ago. I checked throttle cable and its not stuck or anything.. and i would check the idle adjuster under the intake manifold however i doubt its that since it DOES idle correctly half the time.. just not sure why it moves around from stop light to stop light sometimes.. any ideas? maybe IAC vavle needs cleaning?

 

its normal

 

its normal for your idle to vary from 750-1k? How is this the case when my previous civic with the stock motor never did this?

 

yeah it can be normal. almost every Honda motor i'ved had (especially the modified ones) did that from time to time. just a random quick surge or slightly higher rpm idle speed at a light. no codes etc, seemed to be no reason why it did it. but it did so i didn't worry about it.

 

hmm.. well at what point of idle should i be concerned? the highest it gets is 1k so far however if it goes to like 1.2-1.4k should I start being concerned then?

 

from time to time my motor would rev to 1500-1600 rpm just for a couple seconds and then slowly come down. occasionally it would just stick at 1100-1300 rpm and not come down to 800-1000 til i tapped the gas or pulled the car forward a bit.

i would be concerned if the car always did that and often times got stuck at 1500 or 2000 or more rpm. or if i reved up and down, as if it had a vacuum leak of some sort. then i would look into it some more for a solution.

 

cool man. thanks again.

 

Found the culprit..a clogged iac valve.. i took it out.. sprayed some carb cleaner... now it idles like its never idled before!

 

cool, glad it worked out for you!

 

I wonder if I need to clean my iacv, cuz my idle surges only when the motor is cold....it goes up n down around like 1500-1800rpm until it warms up then it drops and feel/sound like the engine is bought to die instantly, then idles perfectly at 750rpm.....everyday

 

According to my tach which I took from a 90 LX my 90 DX auto idles between 400and 900...at 400 its sure quiet as hell.

 

Good job! something to keep in the fyi file.

 

Just try it.. it can't hurt.. at first I thought I messed something up after i removed the iacv and sprayed it with carb cleaner cuz right when i turned the car on it wouldnt stay running.. ahh... forgot to replug the iacv
then i repluged it to the harness and it did start up however it idled REAL low.. almost around 100rpm which seemed like it was about to stall but after about 10 mins of driving it was all good..

 

Just slap those Toda Bs fool.