98 Accord 2.3L with erratic idle speeds

[RER55]

98 Honda Accord with 2.3L has 354,000 miles on it and up until recently ran like it was still new. Have developed erratic idle speeds. When it is cold it idles around 1100-1200 rpm. When the radiator fans are on or the A/C compressor is on it runs around 800-900 rpm. These are normal speeds and great. However, when the engine is warm/hot, in PARK, radiator fans are off, and A/C compressor kicks off, the idle speed drops to what appears to be about a rough idling 500 rpm's and the engine can barely stay running. I've attempted to look for the obvious. Does this sound like anything similar to someone? I own the Honda Shop Service manual if there is a particular component or most likely suspect area I should start at. Thanks

[ATLjunkcars]

This happened to me on a 99 accord 2.3L. It was the idle control sensor

[RER55]

Sounds like I need to get the shop manual headed for section 11-102. Hopefully I don't have to chase this one down to far to get a good fix.
Thanks for the tip and starting point.

[somick]

I believe YouTube ErictheCarGuy has a video on cleaning/adjusting idle control valve.

Good luck,
Sam

[RER55]

Originally Posted by somick

I believe YouTube ErictheCarGuy has a video on cleaning/adjusting idle control valve.

Good luck,
Sam

This reply goes out to ATL and Sam both and will even include a report back to the forum of the post work results.
ATL, you were right on target with the call on the IACV. Sam I did watch the videos, they were very helpful. I pulled the idle air controller off today and cleaned it. I was pretty full of carbon. But with 354,000 miles I would say its worked really well up until recently. I know this is the first time its ever been cleaned because I have owned and driven the car for the past 300,000 miles that's been put on it. In regard to clean, it takes a really thin small fine wire brush to get down in there and do a good job.
Thanks to everyone for contributing to the fix.
So now I have it running again, the fix has a new issue. I went from a very rough erratic 500 rpm no-load idle to a very smooth 1400 rpm no-load idle. Do you think the ECM/PCM will pick up on my new FAST no-load idle and after a few days of driving start to reduce the idle back down in the 700 - 800 rpm range or will I need to manually make a 500+ rpm no-load idle speed reduction adjustment to bring it back into a normal range?
Thanks

[RER55]

[quote=RER55;7180661]This reply goes out to ATL and Sam both and will even include a report back to the forum of the post work results.
ATL, you were right on target with the call on the IACV. Sam I did watch the videos, they were very helpful. I pulled the idle air controller off today and cleaned it. I was pretty full of carbon. But with 354,000 miles I would say its worked really well up until recently. I know this is the first time its ever been cleaned because I have owned and driven the car for the past 300,000 miles that's been put on it. In regard to clean, it takes a really thin small fine wire brush to get down in there and do a good job.
Thanks to everyone for contributing to the fix.
So now I have it running again, the fix has a new issue. I went from a very rough erratic 500 rpm no-load idle to a very smooth 1400 rpm no-load idle. Do you think the ECM/PCM will pick up on my new FAST no-load idle and after a few days of driving start to reduce the idle back down in the 700 - 800 rpm range or will I need to manually make a 500+ rpm no-load idle speed reduction adjustment to bring it back into a normal range?

[RER55]

O.K. a little update. I purchased a new IACV and installed it on the car. While I had the old one off, I checked for battery voltage on pin 2 (middle pin) of the 3P wiring harness. It was 12.7 volts. I checked continuity on the black wire on the same harness as per troubleshooting guide in my Honda Shop Manual. I have continuity. Plugged harness into new IACV module and started car. It now idles 1600 rpm's after engine warms up. I unhooked the wiring harness while the engine was running just to see if the new module made any difference. The engine idle stayed high but started oscillating or hunting really fast and rough sounding. Put it back on, shut the engine off, cleared the code that I created, started it up and still idles about 1600 rpm's. Any ideas, the idle is now so high now that it is effecting how I brake at STOP signs and how the transmission downshifts approaching STOP signs.
Thanks for any ideas, guess I need to getting deeper into troubleshooting in the shop manual.