high fives for engine questions

[REED]

So ive recently noticed that when i start the explorer up it has a really jumpy idle. The engine starts fine and revs to app. 1500 rpm, then it drops to like 1000 and then it starts sputtering and jumps back up to around 2000, this continues and if i dont give it gas it will stall out. The fact that the engine can stall is the part that worries me the most. is this just cause it has been in the low teens when i start it in the morning or do i have something to be concerned with ?

i know that cold starts can be tough on engines, but this seems a little more dramatic than a "rough idle"

thanks for the input guys