Intermittent power to aldl connector

[MJS91]

I have a 91 fwd tsi.It has 3" exhaust,hard uicp,no balance shafts,mbc,2g pistons, head studs,fidanza,and clutch masters clutch,other than that,stock.I'm having a few problems that l have searched extensively and have found little to help.My first question is,Where Does power come from to also(yellow/black tracer)?My Modis gets intermittent communication.The car has NO part throttle driveability,your either accelerating or deceling.I have changed Maf,O2,timing is set,plugs gapped,boost leaks sealed(exceptat 7psi the bov starts opening),tos is adjusted(.66-4.9)sweeps perfect.I took the ecu from my awd and swapped it and made no difference,then bought a capped and socketed ecu from a guy who burned me a custom chip and that made it worse.Any help on aldl question would be much appreciated,help with drivability problem and I'll send the neighbors olady over to polish you helmet.