Been running a sc VR for a while now but everytime it hits 4500 - 5000rpm the car holds back and won't go any further, if you come of the accelerator then back on it revs a bit higher, once its past 5500rpm its fine all the way to 6500. Just replaced coilpack/leads, fuel pump its been re-maped but still the same thing. Its a 2.9, gas flowed head, cams, manifold, sc & aquamist running with an autobox. I think its a electrical issue but any views would be great..