idling

My car idles crazy now again after i fixed the timing chain problem.
everything is good in that area but after a couple weeks of it runnning fine its idling bad again. at lights when sitting at a light it almost stalls. It goes very low then goes back up a lil then goes back down. it stalls once in awhile. i checked and found some oil leaking from the valve cover and when i took it off i found oil had gotten into the first spark plug area. I cleaned it out and put the valve cover back on and its still doing it. wth is the problem any help pls?!?!!?!

It sounds like the piston rings are leaking and the oil is making itself to the top of the pistons, but that means your burning oil which would make your exhaust smoke blue.