I found the cause of oil pooling in cylinder #1 cavity: I removed the valve cover and found the rubber seal at cylinder #1 had come off, it was just lying loose under the valve cover. I put it back in place and re-bolted valve cover hoping that snugly torqued bolts will keep everything in place. Spec calls for 10Nm. 4 of the bolts wouldn't hold torque, they stripped. I'll take care of that tomorrow and then give it a test drive.
Is it possible without that seal in place air was leaking in and messing up the vacuum in the engine, thereby causing the miss/rough idle?