i recently bought a 92 prelude with a blown motor. i replaced the f22 with one that i had from a cb7 accord that i did an h22 swap in. when its cold it runs like hell, the idle jumps up and down from 1000 to around 12 or 1300 rpms. once its warm it smoothes out to around 1100 rpms and stops jumping. but no matter if its warm or cold it hesitates when its held at any constant rpm but revs fine. for example, if i try to hold it at 3000 rpms it tries to stall out, but if you continue the rev or release the pedal its smoothe. anyone have any idea what to try? ive already replaced the idle air control valve

 

most likely it is the idle control valve or the map sensor.

 

also try to reset the ecu using the procedures in the honda service manual. also adjust the idle according to the manual using the adjusting screw. idle should be between 700-800RPM.

 

ive replaced the iac valve already. i thought maybe the iac valve might have just been siezed with carbon from sitting for a little while so i replaced it, but it didnt help.havent tried the map sensor or ecu reset yet. i was unaware that the computer could even be reset. ill give it a try though. thanks for the help. keep the ideas coming

 

Before you keep buying parts you may not need or listening to people who tell you random things to try why don't you click on the FAQ thread, it has multiple trouble shooting scenarios for idle bounce. It could be a handful of different things, read the FAQ before you post anymore.

 

geez mini, i was just suggesting ideas, dont get your panties in a bunch. u can disconnect the map sensor to see if that could be at fault. u dont have to replace it.