UPDATE:
It was the plug.
I drove down and bought a cheap copper Autolite and stuck it in at the Autozone parking lot. Drove it and problem solved - not a single misfire on the graph. So, I drove back to Autozone and bought 6 double platinum Autolites. Took only 45 mins to do the whole job...thank goodness they changed the intake manifold shape. I did not have to remove anything to change the plugs. Easy as pie. I once did a tune up on a 2005 CTS and I had to loosen and move the intake - not so on the new 3.6DI.
It was the plug.
I drove down and bought a cheap copper Autolite and stuck it in at the Autozone parking lot. Drove it and problem solved - not a single misfire on the graph. So, I drove back to Autozone and bought 6 double platinum Autolites. Took only 45 mins to do the whole job...thank goodness they changed the intake manifold shape. I did not have to remove anything to change the plugs. Easy as pie. I once did a tune up on a 2005 CTS and I had to loosen and move the intake - not so on the new 3.6DI.