2000 Ranger start up

2000 Ford Ranger, 4.0 128K 2000 Ranger 4.0 XLT 4x4. The last few weeks in morning when cold 15 to 25 degress the truck will start, but slow idle and runs slow(like it just is not fully started?). After about 1 second it seems like it gets all the computer info( my way of stating what happens) and the idle jumps up and is fine and everything is ok. The truck will start ok if stays warm. This morning the truck will not start. Cranks fine and almost seems to start as described above. I replaced plugs and wires about 2 months ago