FWIW I always run Valvoline full synthetic and switch the vehicle over to 10w30 after 100,000 miles. We have as a family over 2,000,000 miles on GM Trucks. Never had a lifter failure. I have silenced several noisy lifters on used ones belonging to friends by switching them to the Valvoline program. Disable the AFM as others have said.
Also, you mentioned plug and wire change. Run it in the dark and check those. The LS plug wires can be problem prone out of the box. Especially look at the wire in cylinder #8.
Good idea. I think my mechanic as the dealership should have noticed that when he diagnosed my issue. SO I don’t think that’s a problem but I’ll check. I already purchased the stage 1 cam and related parts. Just waiting for them to be delivered. I have worked on cars before and still do my own brakes, hoses, battery etc. The engine stuff I’m going to leave to the professional I’ve hired. Over 1100 positive reviews, 30 years working on Chevys and was also a referral. I’m feeling confident my truck will be in the right hands.