4.0 Idle Issues in Cold

It has to be 0 degrees or close to it for this to occur.

When I start the truck the idle wanders around. It will go up to 1500 then drop down real low and act like it wants to die then back up again. I shut it off and I try again and then it seems to behave.

If the throttle body or MAF sensor was the issue wouldn't it do this other times and not just extreme cold? What about IAC?

My battery, starter, and alternator tested out fine, but I know that doesn't mean much.

I know I could probably use spark plugs.