hi guys

could anyone help me

my cossie is not idling right also popping sounded like the on of the injectors not working turns out there are fine but changing ifound that the fourth injector leed is not working, ie when you take the injector leeds of on 1 2 & 3 the idle drop and on fourth it does nothing?
also checked the power to the injectors and thats fine and re wired it

i have changed

coil
leads
spark plugs
distribution cap
rotar arm
injector

could it the 3 bar map senor or ecu?