Somewhat common issue with these. I am a gm technician and have repaired quite a few of these. Yes gm oil consumption spec-1 qt every 2000 miles is acceptable. If you run in when lower it will burn more. Also an 11 should have the updated afm valve deflector in the oil pan and updated drivers side valve cover with improved pcv operation. These are the first stage of updates performed on an oil consumer, then stuck piston rings will be the cause if these do not help. Have repaired a few that the afm cylinder lifters can stay locked open and will not push the valve causing misfires and cam and lifter replacement is necessary. I have an 06 iron block aluminum head 5.3 non afm. 236000 miles pulls the ice castle like a dream. Does not burn a drop. Also keep to regular oil changes and don’t believe the crap about going longer. The oil will still collect blow by gasses and can do damage to bearings over time. Sorry for the rant just wanted to shed some light on what happens to these.