how do i set the timing 2.5? what do I have to disconect ?

First, welcome to the forum.

As for timing,
1) remove the cigarette lighter face plate
2) jump the bottom right two terminals with a paper clip
3) start the fiero
4) shoot the timing light at the mark
5) adjust distributer to hit 8 degrees

tools needed
1) T-15 Torx-15
2) 13 wrench
3) timing light

hope that helps

thanks Loads !

Also, the 8 degrees is the average of the #1 & #4 spark plugs. Most people say it's easier just to attach the timing light to the coil wire so you see both marks at once.