Hi, Im having trouble with my 2004 gti le rfi bogging quite badly, mostly in rough conditions, wave jumping and tight turning, sometimes down to little more than an idle at full throttle. have checked and emptied and cleaned all fuel tank, line, rail and injectors. seems is either over fueling or starving but black spark plugs suggest overfueling. pump is reading 57psi. Have bled fuel rail fully more than once since re assembly which helps but still not 100% Any help would be greatly appreciated. Cheers.