TF904 w/ lockup shift issue

Im at a loss, and am after suggestions. got an 87 vintage 904 with lockup, and the second gear shift is sloppy at mid to full throttle but ONLY when the gear shift is in second or drive, and it will be sloppy jaloppy when I start from a dead stop, or a slow roll. If i manually hold first, and shift to second (bypassing governor pressure) it shifts nice, hard, and crisp. the shift to drive is always nice and firm whether I go into it manually or automatically, lockup is great as well, no shuddering or anything wierd.
second gear shift is very stiff when im cruising around town, but the second i romp on it, it takes at least a full 2 seconds to hook 2nd.
now heres what ive done:
1. the kickdown adjustment slot is tight to the carb stud, and throttle wide open I have the trans arm all the way BACK to the rear of the trans.
2. I did turn the line pressure screw IN 1 full turn. (im thinking this was possibly too much)
3. the bands are properly adjusted
4. The fluid originally and still is nice and pink, no schrapnel in the pan of any sort.
5. This unit does have a pro-king 1800 stall converter, factory was 1200.
6. Ive checked all the springs and valves in the valve body, and cleaned it very thoroughly twice now, everythings checked out great, and I torqued the valve body to case bolts to 58 inch lbs.

do these lockup transmissions have issues when any sort of stall is thown at them? Also, the only thing to me that would make halfass sense is that im having governor pressure issues, thus making the second gear shift sloppy, maybe when I cranked line pressure governor pressure is having a hard time overriding it? Im not entirely sure, hence this thread....any suggestions are greatly appreciated. Muchos gracias.