well got my immobiliser probs sorted on my mk6 escort (1,8) but turns out the engines only firing on 3 cylinders. im thinking its the injector thats knackered - when i unplug it there no difference in the running of the car.

how do i go about sorting it? is it just a matter of changing the injector or another way? if so would the 1.6 injectors do it?