I have an 86 gt and I had the same problem after a rebuild. It was a combination of timing, to much fuel pressure and throttle butterfly adjustment (idle) that got it to act normal. I also had the black smoke after getting it started. sensers are a pain in the ass but it runs nice now, probably could use a professional tune though. check your tps voltage as well, mine likes about .85v-.90v with engine off and about 38lbs of pressure on the fuel rail. just my .02