So I still have this bouncing idle problem while the car is warming up anyone have any more suggestions??? Here is a list of what I have tried so far, also note these parts were tried off a working 99 Civic Same as mine, same motor D16Y8 AT.

I was going to try the ECU but since it was a manual in my friends car I couldnt get one plug to work so could it be the ECU still?

Anyways heres the list.

Tried the whole distributor. (Car is timed perfectly)

Tried Map Sensor (Same Problem was happening)

Tried IAT Sensor (Still the same problem)

Tried new spark plugs (same)

Tried new Spark plug Wires (Same)

Brand New OEM IACV (It is functioning as I have tried two of them)

Bleed the coolant system.

Checked the EVAP system...

Checked the TPS and its within specs of Voltage..

Tried adjusting idle, but when unplugging the IACV the idle bounces really quick making adjusting impossible.

I unplugged the ECT sensor and started the car. Threw an CEL ofcourse but the car idled high but even, then after about 5 seconds started to bounce really quick.

I have checked all the vacuum lines unless I am missing a magical one somewhere.

At first it was throwing a Code P0505 or idle control malfunction... I cleared it came back again and since have resest the ECU enough where I dont get the chance to see it again.

The Honda dealer was of no help, I only took it there as a last resort and found out nothing but what I already knew.

So basically I am lost I have read many posts about the same problem but never see what they did to fix it. I do not have the FICV since it is an automatic. The only thing I have is the IACV under the throttle body.

Basically I am lost and out some money because of this with no fix in sight. My question is what does the Idle control system consist of??? I am thinking about replacing the ECT sensor, Thermostat and such simply because of the fact once the car is warm it dosent bounce, ocassionally it will but usually just idles high around 1200 rpm at stop lights. The idle screw is all the way in and no change in RPM's. Occasionally too I wil get a bouncy rev when I am so ever gently pushing on the gas pedal going down the street. Basically it only happens alot while in park or nuetral and when under load its like it shows its ugly face occasionally but only 3 times so far since this problem has started. Someone give me some ideas I am dieing here! lol... You people are great to talk to and its nice to know honda-tech.com is here for us all!

 

Try the vacuum line that goes from the intake to around by the valve cover. There is a little black hose there. Might have a whole in it. But the bouncing is called surgeoning. So try to search and ask question for stuff like that.

 

my NA ls set up does the same thing, once it warms up.. its fine. Dont know what causes it though