Problem with performance chip

[NJOHNS]

Can anyone help me,i have had a chip on my 55plate 2.0tdi sport 140 bhp, BKP engine,i have changed the car to an 08 plate,2.0 tdi sport 140 bhp BKP engine but when setting off slowly in first gear i have noticed that at 2000 revs there is a definate flat spot which feels as if the handbrake has been pulled on,can anyone shed any light

[fat controller]

Try changing the fuel filter - made a hell of a difference to mine (although I don't have a performance chip)