Right after a quick run with my buddy going about 135.. i pull up to the next red light and -BAM! bouncing idle. annoying as hell.. it bounces up and down all the way to 2,600 RPMs and back down to 1,000. i have no leaking hoses, no loose vacuum lines.. what the hell can i do to fix it? when my car is barely warming up it stays at 3K RPMs and then does the bouncing idle once its warmed up. my car is a 97 integra GSR with no internal work done at all and just basic bolt-on's keep in mind tho my car was running fine before with the same bolt-on's.
please help!!
Thanks in advance!

 

do a search next time

check your Idle air control valve

 

Most likely what it is! IAVC. Check it up.

 

If the idle is fluctuating after the car is warmed up, it's not the IACV it's your FITV *fast idle thermo valve*

Your IACV controls the idle while the engine is cold, then after it warms up the FITV takes over.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DAguyLS &raquo;</TD></TR><TR><TD CLASS="quote">If the idle is fluctuating after the car is warmed up, it's not the IACV it's your FITV *fast idle thermo valve*

Your IACV controls the idle while the engine is cold, then after it warms up the FITV takes over.</TD></TR></TABLE>

Incorrect. IACV still adjust for things like AC, PS, and raises the idle about 200 rpms. Later models dont even have a FITV. Anyway, it is indeed your IACV and generally the only time it will "bounce" the idle is when you have a vacuum leak or your idle set screw is set too high. Basically your car is idling too high and the ecu/iacv is trying to get it to idle down by pulsing. Unplug the IACV (back of the intake manifold) and see what your car is idling at....if its above 1200 or so then you need to fix that and then the iacv will work fine again.

 

My fault, i thought i read you were in a DA. I miss-read....sorry. There should be in the center of the IACV a screw in plunger (for lack of a better word) and you unscrew and clean it then put it back together.

 

you can not unscrew that screw it is a five side alen tool

 

did you read my *for lack of a better word*?

apparently you got what i meant from my post, so leave it at that

 

I just did the same thing and had the same thing happen - climbing idle up to 2600 and then back down to 1000. I unplugged the sensor on the back of the intake manifold and I heard a little change the moment it came off but it still stayed high.

 

I just fixed it. The IACV (iac - pictured here: https://honda-tech.com/zerothread?id=1291696) was literally hanging off the back of the intake manifold...only one bolt and even then it was working its way out. Anyway, I got another bolt, put the IAC back on and it runs gloriously. Your problem is probably that since I did the exact same thing you did and had the exact same problem (high speed highway run and then the crazy idle).

 

Did you fix it? I fixed mine, just wanting the rest of the forum members to see what your problem was.

 

Maybe its your ******* karma for racing 135 on streets. Tool.

Couldve bent a valve running your friend, by the way, that could create an idle problem.

 

Wow, way to be a douche.

And "streets" and highway are two completely different things. On the actual "streets", that is stupid, but on the highway it is not among the un-anticipated. I have done passes similar to that (not saying that I have indeed have or have not) in my own car on the interstate.

Way to ruin a good thread.

 

This problem just started happening to my 99 Si last night. I've been doing searches on HT to find a solution, but I haven't found any helpful answers.

Ever since I bought this car 6 months ago the check engine light was on, but I always assumed that it was because of a bad/missing O2 sensor (gutted catalytic converter). I've never bothered to check the code.

Yesterday while driving back from class, the CEL would start blinking at idle at stoplights, but as soon as I started moving, it went back to being constantly on ("normal").

I did an oil change afterwards and had a few VTEC runs (for fun and because the weather was cool). Ever since then, the revs have been fluctuating from 900-1800.

After reading some posts on HT, I decided to have a look at my IACV, I cleaned out some of the carbon build up, reset the ECU and that calmed it down a bit, but it still idles high 1100-1300. It wasn't hanging off the manifold in the first place, mine was on securely and is still secure.

I have another class to go to now, I'm going to check the CEL codes when I get home or just hope the problem goes away on it's own..

 

Your car is OBD-II so Auto Zone can check the code for you for free, takes about 2 minutes.

IACV is just one thing to try. Could also be an EGR valve and the diagnostic tool will tell you so.

 

If it's like the IACV it will throw a code... It's that ******' Fast Idle Thermo Valve! To be sure, take your intake off, you will see two holes on the left side of the throttle body, plug one of those holes with something while it's running, and if it stops that jumping idle, it's that valve. Just take the throttle body off. very simple thing to do. There is a plate on the bottom of the throttle body held on by two phillips head screws, take that off. Then you will see a valve in there that will mostlikely be moving around slightly. Thread it back into it's bore, and you are done! I'm telling you, it's not the IACV...

 

nope, don't see the valve and I only have 1 hole

 

wow, isn't the real world a bitch sometimes??

 

I was stating that to the posts creator, the one with the DC2. I am not sure about your EM1.

 

you might want to do a compression check wet /dry also have you been burning oil that might be a clue as to worn rings !!!! then a gain at that speed did your timing slip is a valve hanging open do a compression check if nothing else!!!

 

fixed the leak, less violent fluctuation, but still a little bit. started bouncing from 1300-1500. I turned the throttle body screw down all the way and got it to idle at 800ish. Much better than before!

I'm hoping that once i bleed the coolant, it'll be dandy.