Electrical Problem? Please help
 

Ive got a 95 z in the past year ive replaced plugs wires optispark. My car has been down a few months because of a bad fuel pump. I replaced the fuel pump yesterday. I drove it today for about 5 miles and it started to sorta sputter and the gauges were bouncing back and forth even the mph gauge and all of a sudden it died. i waited about ten mins and tried to restartt it it turned a little and just died. i took off alternator took it to advanced they tested it and said it was fine. i did notice right befor the car died the batt gauge was in the middle of the red. so i bought a new battery installed and car fired right up. it seems to be running pretty good except one weird thing. the batt gauge stays just above the red. when i turn on a signal light the mph gauge starts bouncing. after driving the car another fifteen mins the battery gauge goes into the middle where it should be and no more problems. but then when i go to drive it again it starts all over again untill i drive it for a while. any suggestions

did u clean the battery cable ends when u changed the battery? also clean the connections at the power junction box on the passenger side fenderwell, take em off there and wire brush them and put em back. there is a ground junction there to, look it over and tighten and clean if needed. should be a couple ground straps on the block one in front on the driver side and one a ways back on the side of the block on the passenger side. at least there is on mine. otherwise i would say u have either a intermediate short or the alternators voltage regulator is going. could be that it was working when tested.

Thanks Craby will check all connections and see if that helps .