If the surging is not stopped by pulling the connection from the EACV,
then that's probably not it. Your new replacement part will prove that
you don't have a mechanical air leak on EACV gaskets or a jammed control
piston in that valve (less likely, but possible) By the way, if you keep
your new EACV and it's not the problem, I'd be interested in the old one
(mine is sluggish and causes a surgy idle)

I REALLY don't recommend changing the idle screw setting. It's intended
to be a factory tweak for the throttle body mechanical assembly, and not
modified in the field. If you 'fix' the problem with the idle screw,
then when the real problem is finally addressed, your idle will be wrong
(again) and driveability and emissions may suffer.

As you mentioned, the air boost valve could do it. That would be my next
guess. I don't think it could be the TW sensor, because that's an ECU
input, and the only output the ECU has here is to the EACV (which you
already cleared of blame). EGR could do it also I suppose. That's also
easy to disable for debug - pull the actuator vacuum hose.

Another thought is that maybe your O2 sensor is hosed. When cold, it
runs open loop so the O2 sensor wouldn't matter. When hot, if your O2
sensor were reading rich all the time, you'd be running lean and thus
your idle would be high. If this were the case, I'd expect your mileage
to be up somewhat, but also your spark plug electrodes to be eroded and
your oil temp to be too high.

Do you have a check engine light? Obviously pulling the EACV connector
or mucking with the EGR stuff will set a code, but after you clear those
out, do you get a DTC stored?

Good luck, post back.
Arthur


juni wrote:
> I was told that the EACV and/or FIV could be dirty.I've tried to clean
> these parts and no luck. The idle still surges from 1100 to 1600 rpms.
> The idle is fine when it starts up. Starts at about 2000rpms. It
> seems like it sticks a little though when I slightly throttle it. When
> it is fully warmed up, the idle problem starts. If I pull the
> connector on the EACV when the car is warmed up the idle doesn't drop
> at all. It surges even faster from 1100 to 1300 rpms. If I disconnect
> it when its cold then it drops but nowhere near the normal 500 to
> 600rpm range. I sprayed throttle cleaner inside the EACV through the
> screen and the other opening. I replaced the FIV with a new part. I
> ordered a new EACV. If that doesn't work where do I look to solve this
> problem. Also the idle never goes down below 1000 rpms. I have heard
> that maybe the idle screw needs to be adjusted but the screw has the
> head in the shape of a pentagon. I have not been able to find an
> autoparts store that has ever heard of a tool or bit with the head of a
> pentagon. Some dont even know that it is a five sided shape. They
> keep showing me hex bits. I tried search for a vacuum leak but
> nothing. The only other things left are checking the EGR valve. Air
> boost valve, and the TW sensor. Oh, I have also bleed the coolant
> thoroughly. Any suggestions would be greatly appreciated. You cant
> imagine how many mechanics I ve stumped with this. Some honda
> techs!?!?!?
>
> thank you
>