Well, here is my story.

i have a crx si with a mini me swap.
it has a d15b2 with a d15 vtec head..
the head is port and polised and all that good stuff... ANYWAYS..

after i rebuilt the engine, last summer, it ran like a dream..
then in the winter it would start randomly doing this "fast idol" thing..
it would go from 500RPM to 1000RPM over and over again..
then the beginning of this spring it got REALLY bad..

so, i looked it up and found out what censor it was, and i cleaned it.. well it wasnt that dirty, but i cleaned it anyways..

didnt work.. it STILL did it.

i ended up cleaning that censor 3 times. and STILL it did not work.

finally, a buddy told me to clean ANOTHER sencor. this censor was located on the bottom of the throttle body. so i did, and it ended up being full of nastness and mud and nasty. lol.

i cleaned it to hell and put it back on...

STILL DID IT!

SO. my buddys car blew up, and i took his head off, along with his intake manifold.

i was going to swap the entire manifold, but that center bottom bolt said otherwise..

SO what i did was, i just swapped throttle bodys, and all the censors..

now its not doing it and it runs like a dream =]]

BUT there is a kicker.

once in a blue moon, it will go from normal idol to 500RPM.. it usually ONLY dose this when the car has been running, i turn it off, and a few min later, i turn it back on.. it will just do it a few times and stop..

could this just be an air leak??

its OBD1, and its multi port...
please, please, PLEASE someone tell me what this could be?