I have a 97 civic hx with a gsr swap and si transmission i have a problem with an irratic idle when i'm stopped its contantly revving from 1500-3000 rpms i was thinking that its the IACV but a couple friends told me they think its a vacuum problem. I've opened the hood while its running and listened for leaks so i dont think thats what it is. it has a computer thats labeled B16 so i dont know if thats a problem also i'm hoping that i dont have to put a lot of money into getting it to idle normal. any help would be appreciated

 

Check the iacv.

 

Yeah i unplugged it and it just idled higher than normal but at least it stopped going up and down constantly. So now i'm pretty sure thats what it is