DAZZER

Hi can anyone help im new to the subaru scene i have a 1995 wrx i seem to have a flat spot/hesitant at about 5000rpm when im ecelerating hard. I have put an uprated fuel pump in but seems no better but if i build the revs up slowly above 5000 rpm i dont seem to notice so much. Also if i book it in for a rolling road run is there much they can do becuse the car is a standard wrx and the cost is over £100 i would be greatful if anyone could help.....cheers darren