2011 yukon denali 6.2 removed collapsed lifter on bank 2 and engines still runs rough

[Pedrozo]

My wife and I own a 2011 Yukon Denali, 6.2L  engine, 102,000 miles.  Car was running rough, hesitating, no power, code P0306, replaced all spark plugs, tested coil and wire.  All passed.  Finally had the dealership do a full diagnosis.  Although they did not tell me the problem they recommended changing all lifters, VLOM, of course all gaskets, and head bolts (plus changing oil and coolant flush etc) for about $3950.  I have done the work myself and found a collapsed lifter on exhaust 6 (bank 2, second lifter on cylinder 6, to the left), very happy to find this bc I found at least one problem.  I kept all my rods and rockers in order, also all the bolts I did not have to replace, in labeled containers, greased them with engine assembly grease, soaked all the new lifters in fresh oil, etc. and followed Haynes Auto Repair Manual online to put it back together and take it apart.  The problem is, that although engine runs much better, It still knocks on bank 2, on idling and while running.  I run the engine with the valve cover off on bank 2 and all rockers are working fine.  I noticed that a lot of oil squirts up through on of the two rods in number 6, about 6 inches or so high, like Yellowstone's Old Faithful.  It is a LOT more than all other cylinders.  Is this normal?  Any thoughts on why it still knocks?