13 suburban cammed misfire vac leak??? - SOLVED

Ive bought a 13 suburban with a cam. Guy claimed it rab fine until it didn't as it was his daily. Drove it home with it popping and running terrible. Only code was mass air performance. Once home found the vac line broken from pass valve cover to intake. Replaced line and still had popping. Pulled all plugs and replaced as they were damn near .100 gap and gone. Drove better but still getting codes for misfire and now map performance. Pulled harness for map and had 5 v ref and good ground. Had .3 v on signal wire. Cleaned all grounds. Did motor mount and cleaned grounds on drivers side block. Smoke tested and only intake leak was from missing screw in air box. Yesterday went to get on highway and it went into reduced power mode. Got home and now has throttle body performance and map and maf performance. Im not convinced it was the tune. The guy Drove 40k with no issues until recent. Any ideas without throwing parts at it. ? Losing my mine

Update! I may have found the issue found a post related and the guy replaced his battery ground wire that was rubbed. Also found a loose aftermarket garbage lead for the battery thats corroded and loose. Hoping this solves the issue! Will update

Not the issue. Still getting misfire on cyl 7. Did find my intake hose not connected so made rubber connection. Swapped coils and tried different wire for 7 no change. Ill be doing a compression test 2mrw any advice would be great

Got it figured out! The new spark plugs i installed had cracked porcelain for cyl 7. Now can drive without limp mode. Still getting popping when its cold so will be doing intake manifold gaskets soon. So relieved after chasing my tail for 2 weeks lol now to figure out the various electrical issues

Nice work. Thanks for tagging solved.