[submariner409]

Before you pull the coil cassettes again to check the boots, pull the engine beauty cover and go over the vacuum lines from the throttlebody to several sensors and switches. A bad rubber connector or cracked plastic line will give you an idle miss sometimes. (If a plastic vacuum line is broken, a piece of proper-size rubber vacuum hose from the blister pack displays at a parts store is just fine.) Check the larger plastic vacuum/supply lines for the PCV system, one at the rear cam cover which goes into the intake manifold behind the p/s pump reservoir, the other from the throttlebody casting to the driver's end of the front cam cover. Last but not least, start the car and shoot a tad of choke cleaner or starter fluid down in the area of the hose clamp screw between the throttlebody and intake manifold. Any idle speed change ?? Vacuum leak. There's a rubber bellows "plenum" connector there and they are known to crack and cause a nagging vacuum leak. Easy fix, $40 dealer part. Lots of posts, but c'mon back if that's it.

(What about that PITA rear A.I.R. valve - is the metal flex pipe OK and no exhaust leaks ??)