We have been working on trying to figure out my friend’s bouncy idle at start-up on his 96 Civic Dx w/ D16yz. We checked all the vacuum lines, changed all gaskets on the IM, cleaned and replaced the IACV and still get a bouncing idle. It bounces from about 1400-1600 back and forth. It is throwing a CEL code 14 for the IACV. Any input on this?

 

Start by purging the cooling system of air, following the shop manual's instructions exactly, including waiting the 40 minutes or so for the rad fan to come on twice.

With the code, I would not rule out that your latest IACV is not sound. Certainly double check the connectors to it.

You seen this for troubleshooting the IACV? http://media.honda.co.uk/car/owner/m.../pdf/11-61.pdf

 

Also check your FITV. Its right below the throttle body. There is a thread that shows how to clean your IACV and adjust the FITV. By tightening it a bit it gets rid of the play that causes your idle to jump.

 

I thought that the fitv was only on obd1 and older motors