So I am troubleshooting a missfire at idle. It appears for the moment to be coming out of cylinder 5. I have to validate if it moves to any other cylinder. The problem appears to occur after closed loop (need to validate) or after the car has warmed up, and never under a load. So to me that rules out mechanical issues. Though I'll likely do a leak down this weekend. Looking at fuel trims I notice the long term of both banks goes high at idle after closed loop / idle, but are normal once driving. Short Term appears to be normal. I did fix a small vacuum leak at the PCV to upper intake hose this weekend while looking for unmetered air leaks. Haven't found any others yet. Vacuum seems to stay around 21 at idle even with the fixed hose. Thought's? As a seperate note this car also appears to be about 3-4% richer on LTF bank 2, but LTF trims move up and down equally with bank 1. STF's are in sync with each other at most all times. I am thinking this is a separate issue that may be developing. I have been watch it for about a year. The subject problem just started ocurring.