Toyota Repair: cold miss, service bulletins, coil pack

Question
we have an avalon (OBD2). V6, 3 coil pack setup.
when cold it 'misses' randomly and regularly (kinda comes in spurts).
i have done plugs and wires myself. nothing else ive felt comfortable selling to the customer for the hell of it.

we have a honda/toyota factory scanner with cards. the toyota card has a miss count but never shows anything, and it has never had a code in it.
i have always thought something that is motor wide because of this, like the flow meter or map. i have driven it countless times and watching the graph and have yet to see anything stand out. although for some odd reason the scanner does not give info on the map sensor, though i dont believe the ecu to put as much importance on this anyway.
i know of the egr problems sticking, but it still does it unplugged. and this is absolutely only when cold.

im unsure of what direction to go on this. ive been wondering how the coil pack setup might effect this. they are only 2P and so im assuming fire both cylinders at the same time. could this factor into the lack of a misfire code?

i would be grateful for any help at all

Answer
Yes each coil pack fires two of the cylinders,the misfire monitor is continuous and it should give a misfire code and turn the check engine light on as soon as the misfire happens. Since this only happens when the engine is cold I would start looking at a possible headgasket problem, has a chemical block test been done? If there is any way to get an actual misfire code that would identify which cylinder it is I could be of more help. There were a couple of service bulletins that addressed misfires, there have been a lot of problems with the coil packs, but it will usually give a misfire code (PO300, 301 etc) and the check engine light will turn on. Let me know what year it is and vin# and I may be able to send a couple of service bulletins addressing misfires, please foreward an email address directly to me at tedrttr@yahoo.com