steelhorse

have it pluged in today got lots of codes(12 of) all mention earth ground intermitant guess that mean's going through loom

please help running out of options

its a 1997 5door mk3 vr6

revs free and clean when staionary when driven it surges really bad and i have a massive lack of power till 3 - 31/5k then goes ok accept in 4th and 5th wont pull past 5 1/2k,i have changed plugs coil pack leads maf sensor ran injector cleaner through and its still the same it does seem a bit lumpy too have also done headgasket and since compression tested it all 8 1/2 except one but it was still 7 1/2