i do not have PDR. i do have hptuners software scan tool, so if i can consistently reproduce it, i can record the event. It does feel like a manual bog - like when i try to drive my vintage mustang with a race engine - but when it happens on the CT5 BW, i downshifted from 3rd to 2nd gear to raise the rpms and it continued to do this surging for several more seconds. if it was a bog from "lugging" the engine, then it should have gone away with the downshift? also, i wasnt bogging it that badly at all. it has happened 3 times in the first 500 miles.
During the last "event," i first downshifted to 2nd, but it continued surging, then i upshifted to 4th, and it continued surging. then i put it in neutral and coasted for a few seconds, then it was gone. basically it happened on an on ramp to the GW bridge here in NY (which is 1 mile long), and it resolved by the middle of the bridge. i was traveling 15-25 mph i would estimate during the event.
I am a very experienced driver/tuner/mechanic (have restored many old cars; track both vintage and modern corvettes/mustang; have done a bit of tuning on previous CTS-Vs) - this was far out of the range of normal operation, is quite concerning for safety, and seems like it is coming from the electronics somehow. fuel tank was not near empty.