ROUGH IDLE UNTIL FULLY WARM

[LincolnSedan]

Have replace many tune up items like coils, plugs, v cover gaskets, upper timing chains, new denso premium o2 sensors seem to be a bit smoother idling and driving when warm. car starts in all temps, has power, no bog, no oil consumption, now loss of power. when cold it has a rough idle. after 02 sensors seems like idle evens out when fully warm. have not started playing with fuel injector or anything like sensors. any ideas on what may cause rough idle on a 3.9 colder motor? do think coils are fairly good based on general driving.

 

[SteveOwens]

I would also look at the throttle body elastomer coated metal gasket if the rubber coating may have contracted enought to leak. This also applies to the intake manifold gaskets i use Dei 1500°F degree silicone spray to respay the metal gaskets and mating surface after 1500 grit paper to polish/clean the aluminum before spraying.