ok i have an 89 crx dx and sometimes when i start it cold it will go to like 2000rpm or whatever it is and then to like 500 and back up to 2000, so up and dwn up n down... until i get on the gas. does anyone kno what this is?

 

Is the check engine warning light ON? If so, check the code blinking on the ECU LED under the carpet and below the dash on the passenger's side.

Also try cleaning the EACV (=IACV) (see forum DIY section).

 

check your antifreeze levels, mine does that when its low...another idea is to check your tubing from the radiator, mine had a small hole in one of the tubes and had that sameproblem