Unfortunately, I did not have the injectors professionally checked and cleaned.  Instead, I took the route of a back-yard mechanic and cleaned them with carb cleaner and a cheap injector tester tool that pulses the injectors at different intervals.  They all appeared to have a good spray pattern.  I do have a question that I am unable to find an answer to…  Given that the injectors all have the same part number, are they interchangeable?  In other words, could I swap cylinder 4 injector with cylinder 1 injector?  I’ve read somewhere that the injectors are coded to the cylinder, but with mine being a later model, I wasn’t sure if that applied.