borking/no power

[loll]

recently swapped my engine in to a new shell all works great but in 2nd gear between 1500-2500 rpm it starts borking out until i down gear then change back up at around 2600-3000 no engine lights revs fine out of gear pulls fine other than this small issue if it helps at all the engine is from a 2000 k11 1.4 se the shell is a 1.0 k11 vibe any suggestions for fixing this is appreciated