06 Chevy Suburban 6.0 LTZ AWD Transmission Shifting Problems

The transmission when accelerating, taking off, when
shifting from 1- 2, whenever up or down shifts to 2nd, it's
like it isn't actually in 2nd, when it is. It just revs up and I
either have to feather the pedal or lift off and let it go to 3rd
before accelerating again. Also, it won't shift into 4th gear
(od). I basically have 1st n 3rd gear  working properly. The
trans is only a couple years old, a re-man. With about
15,000 miles on it. Could this be the solenoids both need
replacement, or could the tps need to be checked or the
tcu?  I was letting my daughter drive it, until the trans
strated acting up. I also removed a Nitro ODBD 2
performance chip from the vehicle that my daughter had
been using. The trans fluid is good and fresh. As I have
always made sure reg maintenance performed accordingly.
Could the Nitro Chip messed up the tcu settings n it will
need to be re-programmed ? The VIN #
1GFNK16U26J168284 and it is an AWD model, not 4WD.
Thanks for any and all help with this.