Hidden parameter??

[riverside21]

Still having and issue with trans tune.

To start with I took a drive on the interstate and commanded full torque converter lock thru vcm scanner and have no issues with slipping at highway speeds, even with lugging the engine down and bringing back up again.
Tune calls for zero slip 5 & 6 and increased pressures on the desired table. The issues I keep having, as per feel and log, are that when cruising in 5th or 6th at steady throttle (regardless of load) around 2000 ish engine rpm all tcc line pressure drops to zero. I then get a massive slip, drop under 2k, and the converter bangs back in and starts this cycle over and over unless I either go above or below the 2k range.
I?ve been looking at every table I can find under trans and engine that might command such a thing, but I?m at a loss.

Anybody know where I could look?

[04silverado6.0]

Check your misfire counts in a log.