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Here is the information that you are looking for.
http://dl.dropbox.com/u/11922365/Unit%20Injector%20R%26I%20Yes.pdf << click here
Please let me know if you need more help.
I assume you are referring to copper injector cups, correct?
If so, your truck is a 2003, it has stainless steel injector cups. Not copper cups. They just need to be cleaned with a brush.