Bouncing Idle while cold only

I was having the problem of the bouncing idle and here’s how I solved it.
First, I tried adjusting the idle screw on the throttle body. But that only stopped it from bouncing after the engine was warm. I still had the problem of my idle reving to 3k and then dropping slowly to about 2.5k and and then bouncing rapidly until the engine was warm when it would then idle normally.
Another thing I checked was the coolant level, but that was fine.
The two other possible sources of the problem were bad TPS sensor, or a bad IACV.
Well, it wasn’t the TPS sensor, because after replacing the IACV my problem was solved.

how much was the valve cus i think i have the same prob? and was it hard to change?

I’m going to dig out this topic because I’m having the same problem. Can someone answer YellowTeg’s questions please?

ya how much is the IACV??? I have been wonderin that for a while and now that my car is back on the road… the idle thing drives me nuts…

i bought a brand new one for around $200. save money and go to a junk yard and pull one. I think it is called an EACV, electric air control valve.

Got a used one off a 98 Civic for 20$.

My Fast Idle Valve was messed up too. I took it apart, closed the valve, reinstalled, it’s all good now.

Before you go and replace the IACV, make sure it’s sparkling clean and that the two hoses from it are intact and in good shape. I think there’s 2 12mm bolts holding the assy on. It’s dead easy to pull out (the hoses are harder to get off than the motor itself – lol).

Pull the whole works out and pay particular attention to the intake screen. Spray carb or air intake cleaner into the housing (with motor detached from power source obviously) and let it sit maybe 10min. Shake it around a few times and dump the crap out. I suggest cleaning it maybe 3-4x to get all the carbon and glaze out of it. Also make sure to spray the shaft of the pintle (but be carefull). After everything is dry and sparkling clean, take a 9V battery and connect it the the 2 prongs on the connector for the motor. Make sure you look inside the assy when you do this. You want to hear a slight click and see some movement of the pintle. See the two metal intake hose fittings on the assy?? When the pintle moves, it allows extra air to bypass from one to the other to feed the engine more air when high demand units are being used (such as A/C, defog, hi-beams, etc.).

If the motor moves just a little… you hear the click… and everything is sparkling clean… you are wasting time replacing it IMO. If you want pics, let me know, I just ripped mine down and polished it too. Put a little bit of high heat RTV silicone or Hondabond around the mating surfaces just to ensure a nice tight fit (don’t overtorque the bolts when reinstalling either).

HTH

Andrew.

yeah, just last night my idle started to jump back and forth from 1500 to 1000. what could this be? it happened right after i nearly ran out of gas then filled up again. any ideas anyone? please help!

hey neex, can you help me out man and send some pics please?
i think i need to replace the same thing
thanks dude

yeah neex - pics would be good for those like me with “limited” experience

thanx in advance

wait wait… what is the IACV? my mom’s accord’s rpm’s won’t stop bouncing up and down when idling when it’s cold… i think it might be the same problem

bump

Anyone who had this problem fix it yet? Was it anything besides the IACV because mine has gotten much worse. I’m going to a junkyard this weekend to hopefully find one but if anyone else had any luck, report it pleez