hey i just got a 89 with the i6 in it and it starts hard sometimes takes a few busts to run but cranks fine when its warm it misfires under load where do i start plugs wires are all good

 

Start by checking the computer for codes, then post them here. This thread will explain how:
https://www.f150forum.com/f10/how-retrieve-trouble-codes-obdi-10907/

 

k i checked it out but the pic wont load and what pins do i use

 

With the two terminals at the top and the four at the bottom you will connect the single wire terminal to the top right terminal of the larger plug. If you don't have a check engine light in the dash then you will have to hook the voltmeter negative to the second terminal on the left of the bottom four. The positive of the voltmeter will go to the battery positive.

 

ok thanks i dont have a check engine light i dont believe... is there a battery positive terminal or just jumper it to the battery?

 

Just hook it to the battery.