vw golf gti mk5 55plate help!!?

I had a problem in december with my car, it developed a flat spot and nothimg to peddle at around 70mph, since then after the advice from vw and aa, and my mechanic, ive replaced since december 2013 so recently, high pressure fuel pump and cam bucket that goes on end of fuel pump, dv, fuel filter near tank, coils, air mass sensor, and yesterday it shows low fuel pressure and it spitts and splutters. any ideas please? please please if anyone knows anything about these please can u help. What a car but for all the wrong reasons.