I was on track all weekend with my S. On Fri, it ran great, no problems. Sat at some point it started idling funny, off and on. Sun it continued doing the same idle, off and on. It still runs just fine, when I'm actually driving it. But when it's just idling it goes from 1k to 2.5k rpms. Up and down...up and down, over and over. It doesn't do it all the time though, it's kind of intermittent, but becoming more frequent and constant. I tried the idle relearn, but that had no effect. Is it a vacuum leak somewhere? What should I be looking for? I tried the search but couldn't find anything specific that helped me.

 

Idle Air controller is not working correctly. Or you have a vacuum air leak in to your intake manifold.

Either way, too much air is getting into your intake manifold when at idle.

 

I checked my IAC, via the instructions in the helm, seems like that's ok. I'll start checking all my hoses on Tues. Thanks davepk.

Any other suggestions/experiences with causes of this problem please post.

 

Well, I thought the map whack technique might help your problem, but your describing something a little different...in case you havn't read it though:

https://www.s2ki.com/forums/index.php?showtopic=386868

 

Try this thread, https://www.s2ki.com/forums/index.ph...c=251575&st=25. There is mention of low coolant. Billman and Xviper also have some other input here.

What about a valve adjustment, would that have anything to do with it? I'm far from being a mechanic so nobody make fun.

 

I hope you find a good answer.. I had this problem on my Prelude a few years back and it drove me nuts. I know a lot of Honda guys who have this issue, but we can never figure it out..

 

No help here, but hope you get it fixed for this weekend. see you at VIR.

 

normally a vacuum leak will incur a CEL. Does it do this when fully warm? or when you first start?

 

Thanks for all the help guys, a bunch of good ideas. I figured out today that the problem was with the catch can. The gasket for the bottom of the can had come loose on one side, which was letting the engine suck in extra air. I got it fixed, at least for now, and the car is back to idling like normal Is it just me, or does little crap like this bug the hell out of everybody?

You taking rain tires FF2Skip?

 

lol. thats what it always is. when we installed my supercharger after the second start it threw a CEL and bugged me forever, come to find out a little vacuum hose has a kink in it