Thanks for the advise. It is worse than before. I cleaning it once a year or so and now I am doing it about once every 3 months. I agree that it isn't clear how this is related to the idle, but cleaning it in the past has helped previous idle issues. I chalk it up to more consistent breathing.

Once the car is warm, the idle is consistent. I was thinking about this today and I wonder if my idle air control is starting to go. I clean it regularly also. The IDC looks original so I am tempted to replace it as a preemptive measure.

The throttle body looks great and has always been very clean so the flame trap appears to be catching most of the gunk. I have heard to pull the flame trap in the past, but for this reason I wonder if that is a good idea. I have had the car for 6 years and 85,000 miles and never replaced the oil separator so it could be time for a replacement.

I am also planning to take a good look at the exhaust system this weekend. I noticed that the car has been slightly louder lately and I wonder if I have a broken weld or a loose connection causing a pressure issue. My old Corolla had a bad idle during start-up that was fixed this way.

Lastly, there is a noticible smell of anti-freeze after not running the heat for a while. I have noticed no antifreeze in the oil, but I also wonder if I have a master cylinder issue. Also a possible idle issue.

Thanks all for your great comments.