93 civic idle is surging from 1000-2100 rpm , can anyone tell me why ? How to fix it , unplugged iacv idle was perfect

 

Happening all the time? Only when the car is cold? Only when the car is warm?

 

So I think you just answered your question... you said you unpluged the iacv and it idles perfect. Replace your iacv then. Haha. It can be a iacv, fast air idle or a vacuum leak that will cause surge.

 

Or air in the cooling system.

 

also an incorrectly set idle speed

 

If you unplug your IACV and the idle levels out that usually indicates that you have a vacuum leak somewhere. It doesn't always mean that the IAC valve isn't working. That satually shows that it is opening and closing.

What have you done to your car recently? Have you done any work around the throttle body, intake manifold or vacuum lines?

Surging idle is most often caused by;

- Vacuum leak (hoses or gaskets leaking)
- FITV or idle out of adjustment
- Improper signal from ECT sensor (bad sensor or air bubble in cooling system).
- Dirty IAC valve or throttle body
- Throttle stop or throttle cable out of adjustment.

 

I have the same idle surging problem on my 2000 Honda Accord EX. Does anyone have a picture showing the location of the Idle Air Control Valve? Is it located BELOW the throttle body?

 

The 2000 Accord with a stock F23 does not use the IAC or FIT valves. It uses a Rotary Air Control Valve (RACV) it is basically the FITV and IACV combined into one. It is mounted to the backside of the intake manifold, between the firewall and intake manifold.

 

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/
try searching.