Kickdown timing/injection issues

[Natek235]

Alright guys, have been having various issues with my wagon for some time now. Its just never ending with it. So first issue I'm having is I can't quite get the kickdown adjusted right, either shifts way to soon or too late. It seems to have little acceleration/lack of power. It's also smoking a tone of black smoke, is this too much fuel possibly? About 5 years ago I put a rebuilt inj pump on so could it potentially be injection timing causing me issues? What are some things I can try. It can't get any worse so I'm keen to try anything before I give up on it. Appreciate any tips or tricks for the old girl. Motor is a 4jg2, cheers