would a bad o2 sensor cause the idle to surge back and forth from 1500rpm to 900rpm once it starts to warm up? 88 crx si dohc zc...

 

vacuum leak

 

take some carb cleaner and spray the head (where the intake mani meets the block) and if u hear the car all the sudden idle up or idle down in a certain spot then thats where your leak is

 

well i just replaced all the vaccum lines, not it...then i went and got a new tb gasket put it on and it still idles a lil high like 1200rpm, but doesnt surge, but i havent done the idle adjustment and reset of the ecu yet, but i just put a brand new o2 sensor on ad it still shows a code for the o2 sensor

 

reset the ecu