I have a 1990 Integra with a B20B swap in it (bought like that) and when it was cold it would rev to about 3k and stay there which is way too high and the go up and down while idle then after a while when it got warm it would go to normal about 1k...but recently it wont stop revving up and down from 2k-3k while idle all the time and dont know where to start...also when driving it seems after i let go to switch gears the rev will stay where its at for about 2sec before it drops..and dont know if this affects it but i found out it has 2 holes in the middle of the exhaust system. any help would be appreciated thanx.

 

Start with your checking or just replacing your PCV valve there like 2.70$. My car did the same exact thing and my pcv valve had failed open. It's just my opinion but a cheap easy place to start.

 

Replaced it and still having the problems

 

sounds iacv clean it will brake parts cleaner reinstall. the pcv u can clean with brake parts cleaner as well

 

if the holes in the exhaust are upstream of the o2 sensor, it could absolutely detour the o2's readings. are the holes upstream of the o2 sensor?

 

I Solved it..it was the FITV that was all the way out, just screwed it back in and she is back to new. thanx for all the advice