01itsjustme

I saw a couple very similar threads on this and it leads me to think vacuum leak, but wanted to share other oddities that aren't mentioned to see if it could help narrow it down. Apologize in advance for the length this is going to be, but wanted to capture as much info as I could...

99 Accord LX 2.3L Auto

Started this morning fine, stopped at the store for a coffee, started again and the battery/charging system light, the door ajar lights (all 4 as well as the aux brake light), brake light all came on and engine started surging between ~800-2000 rpm.
Put it in Drive and idles fast, about 1300 then settles down to about 900-1000. Put it in neutral or park and surges again.
While in neutral or park if I rev to about 3000 rpm it settles to about 1100 rpm and idles fine for a while then starts surging again.
After looking here and then just doing a quick visual check of various vacuum lines I start car again. Idles fine, no lights lit. Get to normal operating temp and the lights come on again and idles starts to surge again.
Turn on AC and it smooths out in Neutral and Park and Drive.
Turn off AC and it's fine, though all the lights are still lit. Let idle for 10-20 minutes and no issues, just all the lights still lit.
Rev it up to about 3000 and it starts to surge again, still only when in Park or Neutral. Put it in drive and it settles down to about 900, shift out of drive and surge again.

Going now with a can of ether to spray around and see what happens.

01itsjustme

I took a video to help explain
https://dl.dropboxusercontent.com/u/...%2046%20PM.mov

user456101

Surging idle is usually either a clogged throttle body or a clogged Idle Air Control Valve. It is a whole lot easier to clean the throttle body, and if that hasn't been done in awhile it is a good idea to do it anyway. Scotty Kilmer has a good YouTube video "How to Fix a Car that Idles Poorly". It is also possible that you've got a vacuum leak - a hose has come un-plugged in the air intake system somewhere. Scotty Kilmer also has a YouTube video on "Finding engine vacuum leaks with a cigar"

01itsjustme

So I took off and cleaned the Throttle Body, no help, replaced the IAC and now it idles at abou 800-900 rpm in park and drive, I can't seem to turn the idle up. When I use the adjusting screw it has no effect, I can hear it passing air when I turn it far enough counter clock wise.
Additionally when I rev it up it stalls at about 1500 RPM, tries to catch itself and stalls and repeats that 4-5 times before it dies.
Still no CEL, just battery and the door ajar and rear brake lamp lights lit.

holmesnmanny

When your car is completely warmed up it should be idling at around 800ish. You don't want to turn it up. If you moved the idle adjusting screw then you need to reset your base idle.

On a cold start it should be idling around 1500ish and it will slowly move down to 800ish as your car warms up. This is normal. It's purpose is to warm up the catalytic converter fast.

user456101

From alldatadiy.com

idle should be 770+- 50 rpm

The idle is controlled by the computer in the end. It bases its decisions on data from previous running conditions, so a new installation is going to be different than the situation in which the data in the computer was collected. So, try doing the idle re-learn process. From a cold engine, with no accessories on, and the steering wheel at straight ahead (so there is no power steering load) start the car and hold it at 3000 rpms until the temperature comes up to operating temp and the cooling fan turns on at least once. Then, let go of the gas pedal and let it idle for 10 minutes. If that doesn't fix it you may need to contact someone who has a PGM tester or Honda Diagnostic System like the guys at YourMechanic.com or a Honda stealership.

JPM5

I had this issue on 2000 Accord and cleaned the idle control valve mentioned above and it fixed it immediately

Firstcar

I would also suggest cleaning the idle control valve. It seems hard to do,but is really 2 bolts and three hoses; coolant feed, return and vacuum or vent, not sure which. Do this while the car is cold, some coolant will spill. The 2 bolts are 10mm.
This valve is located on the back of the intake manifold towards the left next to the throttle valve. I use carb cleaner to get all the gunk from the valve mechanism.

Let us know