4L80E problem over 6000RPM 1-2nd shift Please Help!!

Hi I have a 1989 Caprice with a 2008 6.0L LY6 with a LS3 cam / 4L80E with transgo hd-2 shift kit the car was tune on a dyno but I'm having problem with the transmission, when I make it shift from 1st to 2nd gear over 6000rpm it seems like it goes in limp mode. In scanner mode you can see that the accelerator pedal is at 100% to whole time but the throttle position start to drop and you can fell the limp mode and then shift in 2nd gears , but from 2nd to 3rd I can shift it over 6000rpm without problem . Also I'm having problem with the throttle response it seems to be slow under 4500rpm

thanks