2001 Nissan Quest

Engine Mechanical problem
2001 Nissan Quest Automatic 162000 miles

I HAVE A PROBLEM WITH CYLINDER No.3. NISSAN DIAGNOSTIC IS FIRST CLEAN INFECTION SYSTEM.
INJECTOR WAS REPLACEDFOR A NEW ONE AND AFTER A WEEK THE PROBLEM STARTED AGAIN.
NISSAN HAS 2 DIFFERNT INJECTOR WHITE AND YELLOW, BUT THEY DO NOT KNOW WHICH IS THE CORRECT ONE.
THE ORIGINAL COLOR OF THE INJECTOR IS PINK AND DOES NOT HAVE ANY WHITE OR YELLOW MARK. NOBODY KNOWS HOW TO IDENTIFIED THE CORRECT ONE.
PLEASE ADVISE WHICH IS THE CORRECT INJECTOR AND IF I HAVE TO CHANGE SOME INSULATOR INJECTORS ALSO.
THANK YOU