I'm rebuilding a 260Z and desperately need some expert advise on an electrical problem. Each time I start her up the oil, temp & fuel gages work fine for a few minutes then they become erratic and go to zero. All three are on the same 10A circuit as well as the turn signal, tach & choke warning light. The amp gage works fine but doesn't go thru the fuse box. I've traced the gage grounding to the alternator housing and have continuity. The alternator and regulator appear to work well, 12volts at idle and 14.5 @ 2000rpm. Neither tach nor turn signals work properly either. The tach pegs to the right at start up and may occasionally drop back to proper rpm. Turn signal flashes fast on right turn (both front & back are flashing) and nothing on left turn.