I'm wondering if the base timing is still off, even though its a huge PITA to check it, that might have to be the next step. Unless one or more of the valves took a hit due to the mistimed valve events caused by the shifted reluctors on the original cams.

 

Before I pulled the valve cover to check the reluctors, I had the dealer confirm the code and manually command the cam position actuator solenoids with the Tech II to completely rule them out. They said the scan tool wouldn't let them test the actuators because the fault codes were set and would come right back on after clearing. Dealer confirmed reluctor inspection would be necessary.
I am torn on what to do next because either GM's reluctor service bulletin is wrong, the cams are wrong from the factory or I have other issues related to phasers, actuators or base timing???
When removing the phasers from the camshaft, they made a snap noise and rotational movement, seeming to have a residual oil pressure preloading them.
Could the ECM be sending the wrong voltage signal to the solenoids and causing incorrect valve timing?

 

I installed new cam actuator solenoids today and the problem still exists. I will be diving into the fun job of checking the base timing when I get some time this week.

 

Pulled the timing cover and turned the engine over 6 or 8 times until the three marked links lined up. It looks like the chain skipped 1 tooth on the crankshaft sprocket. I think I will have to replace the chain, crank gear, tensioner, guides, and both actuator gears to be safe. Not sure if I can get a kit with all parts that I need. Can I replace the chain when the cams are at overlap and not on the compression stroke?

 

Got all the parts I needed and found that the right timing chain guide was partially broken. Replaced both actuators, guides, crank sprocket, chain, tensioner, timing cover gasket and oil sprayer. Buttoned everything up and now the car is on the road and running fine with no service lights.

 

Great to hear!

Glad you're back on the road after such an "adventure".

 

Here are some photos of the chain guide that I found was broken. The pieces are most likely in my oil pan right now.
If anyone needs a couple good cams, cam sensors and crank sensors, let me know.