Cold Weather Cylinder Miss at Startup, V6

[ThunderVan]

Hello from the frozen wastes of Thunder Bay!

My van is L400 with the 6G72. We've had some properly cold weather lately and a new issue has arisen. Below -15C, and certainly at the -30 we've been having, my van will start but it only bangs on a few cylinders. After a few seconds it comes around and then runs fine. In three winters this is the first it has done this. The block heater is working but makes no difference for this problem. No engine light.

I've searched and found some mention of cylinder miss here and there but almost always for the diesel and never for cold weather startup for the 3L.

I first thought fuel system. Maybe the injectors are wearing out. Ran come cleaner through a tank but no help I'm replacing the fuel filter because I haven't yet and now is as good a time as any but I've had no trouble with fuel/air delivery. Air filter is clean. The engine runs smooth and strong once warm.

Plugs were replaced the summer I brought it over. I'd pop them out to have a look but that's such a pain on this thing,

She's over 106K on the odo and I have not changed the timing belt yet. I know, I know... don't yell at me I just didn't get to it before the winter hit and I don't have a warm place to work!

The only thing I did that could possibly affect air/fuel is an adjustment to the throttle cable. I noticed very minor slack at the adjuster, barely noticeable without manually moving the butterfly arm dealy. So I firmed that up but not to the point of having the butterfly open at neutral throttle. I figure it I'd have noticed any problems with this adjustment before the cold but you never know.

If anyone has any ideas or can point me to a post I've missed please let me know. Maybe she just doesn't like the cold.