Now that my IC pipes are hooked up properly I have only one other issue I am trying to figure out. If the car is cold and I start it, no problems. It fires up idles around 1400as it slowly warms up and then around 60 degress or so the idle falls to around 900, no problems. If the car is Hot, IE been sitting maybe all of 10-60 minutes it fires up and idles right around 900 no problem. Here is the confusing part. If the car has been sitting for about 90 mins to 2.5 hrs (PFC Commander says watertemps are ~45-55ish) then it fires right up sits at 1400 RPM for about 5 secs and then it goes through this cycle:

1400 RPM down to ~ 450 Rpms up to 1400 rpms down to 450 rpms. It does this over and over until the water temps hit about 65 and then it idles normal. BTW, the car sounds like it is about die, but it never does. Just kicks back up to 1400ish

This doesn't happen all the time, but I have definitely noticed with the cool spring evening air it happens more frequently. The car was tuned a year ago.

PFC is my ECU. This is really the only problem (knock on wood) I have with this car. I searched through a few threads on hunting idles and none of them seem to be what I am experiencing.

-Don

 

a hunting idle on a hot start is usually the result of a somewhat lean mixture confusing the ISC. The engine pulls a little less vacuum on hot start, and the IAT sensor heats up as it sits under the manifold. Those two factors results in a bit of a lean mixture, which affects the idle stability. Ported engines need a bit more fuel at idle to stay stable. Do you have a wideband? What is it reading when it surges like that? The problem can be fixed by adjusting the fuel map and IAT correction table with a datalogit. I've done it before, it just takes time.

 

I have not invested in a Wideband as of yet, although it is next on the list of updates. This is something I can live with in the mean time. Thanks