i have a 00 civic si with 90k miles completly stock my check engine light came on for iac idle air control vale so i cleaned it put it back on didnt go off.. so i bought a new one put it on and it didnt go off.. my car idles at 1500 warmed up the idling goes up and down when iam driving and let off the gas it trailerhitches like bucks what can i do to resolve the problem thanks

*when i unhook the connector to the iacv the idle comes down to normal

 

the iacv and map and tps sensor all relay together your best bet is to switch all of it out, and the codes dont always go off you may need to reset it manually or erase it with code reader

 

the iacv,map both relay together so try both and the codes dont always just go off you may need to manually reset or erase with code reader

 

seems like you want me to just throw parts at it

 

bump

 

Did you reset the ecu after you swapped out the IACV? could be the wiring for the IACV if the new ones still throwing the same code.

 

how do u reset the ecu i just unhooked the battery

 

Unhook battery for about a min then hook it back up..

 

i unhooked the iacv connector and the high idle stopped

 

I had the same problem. Except I cleaned out the IACV with Seafoam Deep Creep AND the throttle body with the same chemicals. Hums peacefully at about 700-800RPM idle.

 

Reset ecu cel came right back

 

bump

 

Is the new IACV brand new from honda?

 

yes brand new

 

bump

 

ttt

 

well if you got the right IACV and its not defective, it could be the wiring or installed wrong. make sure the iacv itself is not causing a vacuum leak where it connects to the manifold. i found out on my car i had to disconnect the batt for around 10 mins for the ECU to reset completely.