Hey.. I just did a swap and put a 92 OBD 1 LS motor into my 90 civic... I'm getting only one CEL code, CODE 14... which is IACV, My RPM's also bounce till I get to bout 2k then it's smooth after that... No vaccum leaks, and I just cleaned the IACV with carb cleaner.

THANKS!
Mark

 

try the simple first , do you have enough coolant in the system ,Also did you get the air out of the cooling system (this can be hard to do) Must be bled or it will cause all kind of surging. Joe Sr.

 

back from the dead..im running into the same problem, could anybody help?

 

had the same problem what i did:
take the iacv off open the end of it. its 2 philips / hex screws. in there there will be a white plastic screw that screws to the inside of the iacv. In the middle is a shaft.. just screw the white plastic back down in to place and then put it back together and you should be good to go... good luck