2016 Tahoe MIL comes on and goes off

[Carolinakriplers]

Hi all new to the site looking for some helpfull info with my 2016 Tahoe. My wife was on her way home and was going over a bridge and the CEL came on and started flashing. After crossing the light went off and did not come back. She pulled over to check things out and said she could hear a tick sound coming from engine bay. I scaned it and had a cyl #8 misfire so I swapped coils to see if skip would move and it did not. Now I am getting a random cyl misfire code and when the light comes on it flashes and goes away. I have changed the plugs and wires and even tried a coil pack for fun. With the tick its almost sounds as if its a collapsed lifter but that doesnt explain #8 misfire. Pulled valve covers rotated engine and all rockers move like they should with no play. Its an obvious tick that is diffrent than the injector ticking sound. Any info on this would be great thanks.