That right there was the first thing that popped in my mind. I had the same issue after it was warmed up, and especially when the TC locked up at highway speeds.
It eventually got so bad that it would buck and kick while downshifting like coming to a stop.
Wouldn't WOT be affected then? Thats the only time it really dosent show any noticable issues at all. Seems to be at 1/2 and lower of the throttle range.
2001 Regal-GMPP handling, shift kit, tuned, ported Gen3, 3.6, N*, SLP dual catback, Aeroforce
70 Monte Carlo 12.5@109 waiting on new setup