1990 5 speed STD Civic hatch. I've been experiencing a slight issue with my idle. When I am actually stopped, the idle is fine, around 850 rpms or so. The issue happens when I come to a stop. As soon as I stop, the idle will drop all the way down to 400 rpms, shake slightly, then bounce to 850. This happens in a span of 1 second. I had put in a new IACV (was experiencing this with my old IACV as well) and had done the DPFI to MPFI swap awhile ago. I have a fairly new distributor, spark plugs, wires and fuel filter. The car runs great, just this one issue. If anyone can help me out, or at least point me in a direction, I would appreciate it.

 

have you run the idle set procedure as detailed in the factory service manual?

 

Thank you for responding.

Yes, I believe I followed all the steps:

1) Disconnect IACV from wire harness
2) put jumper in connecter by passenger footwell
3) adjust idle screw so that idle is around 850 rpms
4) turn off car, reconnect everything, take jumper out.

Let me know if I missed anything.

 

Just thought of something, when I switched out the IACV for the brand new one, I did not reset the ECU. Could this be causing my problem?

 

If you warmed the engine up until the fans come on once and then set idle that should be it, though setting at 850 seems a LOT higher than the manual had it for my 1989 crx, but i dont have the factory manual here on this computer though. for some reason i think i set mine at 450 ish.

 

i am fairly confident that no load warm idle with IACV UNplugged is supposed to be 450rpm