i have a 90 crx hf with a full obd0 ls swap and when i start it in the morning it jumps in idle from 2-3thousand rpms only untill it gets hot ,then it idles fine at around 800
ive tried replacing the iac valve with others ive had laying around in my garage but all does the same problem. any ideas of what it could be ? thanks

 

bump please helpp

 

um dude its saposed to do that, thats what warms the car up quicker then drops the idle down when its warm

 

nahhhh u dont understand ,the idle goes back and forth from 2000 to 3000 back and forth untill it gets hot, its not a vacume leak and i replaced the iacv 3 times with other used ones so i dont think all 3 were alll badd

 

vacuum leaks would usually make it bog down really bad when you tap the gas. however you might want to try cleaning out (or replacing) the iacv (on the back side of the intake manifold) that controls cold idle. this is a relatively common problem on those engines.

 

Have you checked the fitv underneath the throttle body?