Thank you for that information.
If your truck is equipped with active fuel management (AFM) there is a TSB from GM that tells you to replace the lifters in pairs as well as to perform the following procedures using a dealer-level scan tool:
Cylinder deactivation (Active Fuel Management) system compression test in SI. If the running compression of the misfiring cylinder stays below 25 psi regardless of the AFM solenoid being commanded on or off, the AFM lifter is mechanically collapsed/stuck or unlocking as soon as the engine is started.
* Cylinder deactivation (AFM) valve lifter oil manifold diagnosis and testing in SI. If the test above isolated a possible AFM lifter concern, it will lead to this test, which tests the VLOM (Valve Lifter Oil Manifold) for proper operation. SI states a limited amount of air will leak from the bleed holes and outlet ports even when solenoids are off, and compare the amount of leakage to verify all 4 solenoids are operating the same. If it isolates a concern with the VLOM, replace it and re-evaluate the concern.
* If the tests above isolate an AFM concern, or if no rocker/valve movement is noted with the valve cover removed, follow SI repair procedures to replace the pair of lifters for the related cylinder. Before installing the new lifters, blow out the related lifter control oil passages with the old lifters removed. Also, inspect the VLOM oil filter under the pressure sending unit for debris/sludge and clean or replace as necessary.
* NOTE: Please follow the diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.