Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Have you swapped the coils at all? and the bad news for being bank 1 is there is an updated head for this year as they had a lot of problems with misfires on that bank, if you end up getting a head make sure to get new actuators as well the new design requires 2012 or newer actuators. was there any evidence of oil in your spark plug tubes?
have you done a leak down test on the suspect cylinders? this can often find problems not seen in a compression test. can you shoot me your vin so i can check which model 3.6 you have
ok you have an ly7 engine so i would check injector flow and suck in a lot of top end cleaner through a vaccum line as these can get a lot of carbon on the valves, if you have leakage on the leakdown test, cleaning the valves this way can often fix it.