I was doing some searching on injectors recently here, and came across a series of posts by "Beagle" - he made a good point against using diesel purge. It loosens up crud in the injector pump and puts it through your injectors. If your injectors are crudded up, then by all means take them apart and give them the disassembly and cleaning that they deserve. There is a good MB tech bulletin on cleaning injectors that I found posted as well. Search injector and cleaning.