Have to make a decision about fuel injector replacement or not. Situation, 2008 Sprinter 2500, 3.0 meticulously maintained., 345,000 miles Absolutely no indication of fuel injector problems (smooth idle, no smoke, decent fuel economy (up to 21 mpg highway loaded, 17 around town). #6 and possibly #4 injectors have just begun to leak (almost no tar residue around the injector). Replaced the injector seat in #3 about a year and a half ago. The correction values are 27 for cylendars 1,2,3,5 and 33 for cylinder #4, and 17 for #6. Please advise if I should replace all my injectors now? Or wait for symptoms. Of course I will be pulling #6 and possibly #4 to replace the copper seat. Any advise is much appreciated.