its for the solenoid valve not the actuator - change the solenoid valve with a new gm valve - just because it measured 12 ohms and within spec doesnt mean anything to me. put your meter on and grab the head of the solenoid and wiggle it - your readings will probably change.
There is actually no part that is just called "actuator" in this system, so pardon my poor terminology. The "actuator solenoid" is commonly called actuator for short, but we are talking about the same thing, unless you maybe are referring to the sprocket/phaser?
Michael, I forgot to ask if you are using the correct weight oil and a good filter and changing it regularly? I have seen some videos of these solenoids that get gummed up a bit from low quality oil. They then get sticky when hot, and don't open and close properly. The whole VVT system gets bunged up when the oil starts to sludge or debris builds up. I believe that is what I am dealing with.
Is your timing chain tight and quiet?