2008 Acadia has low compresion on 1 cylinder?

metalman2017

Could it be the oil and filter needs changed?
Or is the VVT cam Phaser Solenoid letting the valve not seat not properly closing the valve
Burnt valve?
Broken valve spring?
piston rings gummed up?
Under half to full throttle it doesn't miss a beat and pulls good
When started it runs smooth for about 30 seconds and then starts the misfire with MIL on.
Replaced coil packs and ACDelco Iridium spark plugs at .043 Gap, runs the same afterwards.
Bad injector ?
Need help with this

1ronster1

FIRST -WHATS THE COMP READING ? AND HOOK UP A OLD SCHOOL VACUUM GAUGE ---IF IT DANCES BACK AND FORTH ---THAT BAD ---IF IT 21 INCHES OR CLOSE AND SMOOTH ---YOUR GOOD---BAD INJECTOR ---HIT WITH A LONG EX 3/8 --SNAP ON -----IF IT KICKS IN ---YEA ---AND THE CK ENGINE LIGHT SHOULD GO ON --CODE ? -----RINGS -----REV THE ENGINE --THE VAC GAUGE SHOULD WAY UP AND WAY DOWN ON A SNAP ---AND WHEN YOU TAKE A COMP TEST --DO 1 DRY ------2 PUT HEAVY MOTOR OIL DOWN CLYD --( about 2 table spoons m-when you start it --rev it --will smoke like a MF till clear ) --THE READING GOES WAY UP -WORN RINGS - OLD SCHOOL --LIKE ME --1RONSTER1