TCC Problems

Trying to help a friend fix his TCC problem. Here is what i'm working with.

trans is performabuilt lvl 2 4l65e, converter tci 3500 stall.

when cruising at 40 + mph the torque converter will lockup for a mile or two and unlock for maybe only a mile and repeat. sometimes it will stay locked up for 5 miles or stay unlocked for 5 miles. its inconsistent, but it will not stay locked up even with cruise control on it intermittently locks and unlocks. this all occurs in overdrive. also with converter locked at around 45 mph when releasing throttle the converter stays locked up 0 % throttle until reaching around 35mph or applying brake pedal.

I'm thinking its the trans itself but just wanted some opinions.

sounds like the misfire monitor needs to be adjusted/disabled and its normal to stay locked

Thanks for that tip, looks like it could be the issue. The car is a 99. I tried finding a 99 file with a stall that had that changed to look off of and couldn't. Would a 2000 be the same? 1999 looks way different as far as the values.

Check out my tune. I had been through a lot trying to get this here but this tune is running good and I feel like the tranny is perfect!