I have 3 dead cylinders. I need help, I belive its the Computer but im not sure.
any suggestions?

 

check inj pulse on those three dead cyls with a noid light if good, check for spark on those three cyls with inline spark checker, if good, do a compression test.

 

Well, I solved the problem. Apparently my computer went bad and while checking the car it seems I put the spark plug cables in the wrong order. So I fixed the computer and put the cables in order and my Stang is running like a champ!!