MikeGyver

iTrader: (5)

That should just be the fresh air pick up for the PCV system, with a tube on the other side that goes to the right valve cover. Restricting the air going through the PCV system will very much affect your idle tuning. PCV is a finely tuned part of the idle system. The symptom that you described in the first post can be tuned out by adding idle air to the idle air base airflow and throttle cracker tables, or by removing the garbage from that hole.

By the way, it is normal to have a lot of cells in the cracker table at zero.

MikeGyver

iTrader: (5)

If you want a real reason to have to learn idle tuning, put a cam with a little overlap in there.

RSTinOKC

iTrader: (2)

Thanks for all the input, now I know where to start. It would be good to get a feel for idle tuning as there is a cam install coming in the near future.

Update: Added 2g/sec to base airflow over lunch today and it seemed to help a bit. In the past I've skimmed Krambo's Idle Tuning Guide but I always thought it applied more to cammed vehicles...seems to be one of the better guides out there. I'll be going through it more closely this evening.

RSTinOKC

iTrader: (2)

I finally got this idle problem remedied over the weekend. I noticed that when the dip occured timing was way lower than should have been commanded. The idle overspeed table was the culprit. Values above 150 were waaay to agressive...added about 5* past 150 and problem solved. Still needs a little bit of tweaking but for now I am happy.