Idle Relearn?

[RevGTO]

A couple of months after installing a ported TB, when I installed my homemade CAI, I started to get a "cruise control" effect on decel. Plus when I came to a stop, the idle would hang at 900rpm for a second or two, and then slowly descend to the set idle speed (A4-650). I did some scanning and was getting set to do some tuning and then the behavior disappeared on its own.

It reappeared a few weeks ago when I changed to an 02 OS, and has been there consistently since - until today, when it stopped suddenly and the car reverted to normal (at least for the time being).

My question is, is this something that the PCM "relearns" and adjusts? If so, what is involved and at work here? Thanks for any info - just want to learn.

[Tordne]

There sure is. There table that generally cause the cruise or surge like that s the Desired Airflow table (B4307).

There is an amount of learning that can be done by the PCM, limited t the values in B4521.