When I start my engine, and especially when it is cold outside, my idle is almost non-existent and the engine will occasionally stop by itself. Once it gets warm, this problem resolves, but when it is relative hot outside, and the engine is warm, it start idling like crazy in a pulsating matter, basically runs up for a bit and drops down again. If I rev the engine at that time, it often idles better, sometimes within normal range, or at least not as fast as before. Ideas of what is going on?

 

I had the exact same issue on my gsr. Low cold idle and high pulsing warm idle. But i had the iacv and the fitv both unhooked. So i took both the iacv and the fitv off and cleaned them really well and hooked them up the way they should be and it stopped.

So what im sayin is clean the iacv and fitv and you should be good. And try rebleeding the coolant system.

 

I was thinking bleed coolant test tps clean iacv easy things first
Have you done any work on it before this problem?

 

common problem in Honda's with FITV's.

I agree to start with easy probable causes first, but these may shed some light on the subject.

 

Most of the issue was solved after I found a small leak in one of the vacuum hoses....