Car: 1992 Civic Si hatchback, with a B16a2 swap (done by a friend).

I know a tonne of you have had idle problems, and I have read the faq's on idle questions, and I have searched, but I am wondering if anyone has had a very similar problem to mine, so perhaps i wouldn't have to go through all 50 methods of solving the problem. (I'm a full time student, and am planning a wedding with my fiance. I pretty much have no free time at all. blah.)

Here's a clip
http://www.youtube.com/watch?v=rvKUO6f4A2Q

Basically whenever I idle (after warming the car up a bit), it does this. Stabilizes at 2100ish, and then drops to 1000, and then jumps back up, and drops back down. (I was in traffic recording, so I didn't have much time to let it repeat 50 times... but it will if I let it...)

Thanks for any, and all help. It's so appreciated. Now it's time for me to get back to physiology, pharmacology and anatomy.

 

What methods have you tried? That problem 99.9% of the time is one or a combination of the following-
Dirty IACV, dirty FITV, vacuum leak on or around the intake manifold (vacuum lines included), vaccum leak from the throttle body. Have you tried spraying the hell out of the intake manifold, lines, and throttle body with brake clean or carb cleaner. If you do attempt this be sure not to spray the alternator.

 

check the IACV.
also check the FIT Valve (under the throttle body, if you have one).

 

check your map sensor, i had a gsr that did that idle surged, got the map replaced and it was fixed. did your friend do any rewiring to the engine harness?

 

my car started doin this like 3 days ago. did yours not let you shift either if it was higher up in the RPM? was quite irritating.
took the FITV off and fixed it up(tightened the valve mine was wicked loose.) it takes bout 10 minutes to do and all you need is a 10 and 8 and a screwdriver.

my car runs like a champ now. id say check that then go to the IACV.

 

I had a similar issue and it was my IACV. I need to replace it altogether, but I cleaned it for the time being and the car runs fine. The only real issue at the moment is some minor idle fluctuating, but I want to change my spark plugs again now that I've finally gotten around to my oil change. I will look into the FITV. I had, IIRC, some oil on the map sensor and that also helped. GL!

 

Check for vacuum leaks or if one of the vacuum lines came loose. That fixed something like that for me once.

 

This is a straight up IACV issue. You need to clean/replace the IACV.

 

every time i see one of these threads i post this..

https://honda-tech.com/forums/showth...light=fix+fitv

BTW u need to get some gas..