how can i fix my ford mondoe 2.ol glx zetec engine?

it is missing like no other im sure its not the head cos theres no smoke it seems to be fireing on only 2 . My friend and i took 2 of the leads off and the car still running , but when we took one of the other leads of it cut out like its was supposed to do PLEASE HELP its a present for my lad who is 25 this week