b18c1 cold idle problem
 

Engine is a b18c1 using a vafc 2 for a fuel controller. It idles at about 2700 rpm when you first start it up (cold start), then when it starts to warm up the idle will fluctuate between 1200-1700 rpm, then finally after it warms up, has a perfect idle around 800.
Any ideas what could be causing the problem?

Think i may have found out what the problem is...
http://www.honda-tech.com/zerothread?id=1564019
Gonna give it a try.

if anything, I would look into replacing the hose that passes coolant underneath the throttle body, it was pinched once, I fixed it but didn't buy a new hose and that could be a problem.. but I doubt it since if that is plugged the idle will NOT drop past 1500rpm for more than 30 seconds at every stop light. just a thing to check.

Had the same thing happon on my lude. There is an iac that controles cold idle its the smaller of the two on the throtle body. There is a plastic diaphram that backs off over time. Remove the valve and screw it in clockwise. should stop the serging idle.