RedEj8

So every now and then my car has a terrible idle when i first start it up.It usually does it when its cold but it has also done it warm. Its like a really bad missfire and sounds as tho it only runs on 2 cyls. I have to give it some gas for a minute or so and it will eventually even itself out. Ive already changed cap,rotor,wires and plugs. Ive also cleaned out my IACV. My only guess is its something in the distributor going bad perhaps a coil or ignitor?
It doesnt do this all the time, its very random like sometimes i will go a week without it happening. Oh yea im also running on openloop since i had a bad o2 sensor when i got tuned(crome), maybe that has something to do with it? Any insight is much appreciated.