[jack]

i have to replace one injector can i put one that dont have the same
cod and jest replace the nozzle does the base of the injector is the
same in all engin that use them ?

 

[chittychittybangbang]

They should all be the same diameter. I believe that they are made in sets so that they are all matched and relatively balanced. If you have cheaper nozzles or have 1 new nozzle, it's possible it will not be as balanced and would benefit from a balancing.