I guess I should have stated that when I export to PDF in AutoCAD it is faded and also when I use the plot feature and I plot it to PDF (because I have the full version of Adobe Acrobat) it is faded. This is not a printer issue but maybe an issue with the program or the file. I will post the file later tonight after I get home and maybe somebody can try and print to see what I am talking about.
Are you viewing the PDF at 100% zoom? Adobe scales down the vector data so when you view on screen, at less than 100%, it looks thinner/grayer. It isn't when you plot it.
If the drawing has colored lines than .PDF will show your problem. When I print an ACAD drawing using CutePDF, I turn all lines black in my ACAD format otherwise I'll have the same problem.