I had this happen to my 2001. It was the IACV. I replaced it and everything was fine again.

 

well its not really in my hands anymore, unfortunately...the service dept said they tested out the IACV and it was fine...and they said it was the ECU...so now its at Honda waiting to get looked at...hopefully (crosses fingers) it'll be done soon...

 

UPDATE: Got my car back today from honda and they replaced the IACV and supposedly the ECU as well...whatever they did it runs perfectly now and pulls EXTREMELY harder (maybe its cus i got stuck with a cavalier as a loaner and i just missed the s2k too much?)...the vtec transition is incredibly noticeable and its just so much fun to drive...