Foriogmc

Alright I have a Sierra 1500 6.0 with afm. We had a failed lifter in cylinder 6 with a bent push rod we did a top end repair with the following parts replaced: all new melling lifters melling pushrods new lifter guides new oem camshaft new oem spark plugs and wires new oil pressure sensor new valley cover Truck runs great and goes into 8 and 4 cylinder mode fine but I get a random tap sound coming from the passenger top end. The weird thing is it comes and goes. I’m lost as we pretty much replaced everything top end wise and done think this is a Normal valve tap/click as they are new and seems to be louder then just a click. i went to a dealership thinking I should just get rid of the rig before she blows again, funny thing was the salesman said you thinking of trading this in because of that tapping noise! I didn’t tell him about that hahaha. love the truck but I’m lost of what to look for or fix next. any suggestions or help would be appreciated. Happy 4th!