Digital BW, The Print

Just when the 7600 seems to be working ok the 7000 now prints a mottled B&W
using Mis FS ink and IP5. I did load to new cart recently the yellow and
magenta. I also loaded IP5 but I believe it was before I had these problems.
I printed a step wedge and compare it to the IP5 window and it appears the
darks go much further along the scale than they should. I have tried
different tiff files, profiles, and they all seem to print with the mottled
look as if I fine coat of gray was added.

Has anyone heard of bad ink or miss marked ink from MIS. I do not know were
else to go with this, for I have printed great B&W for the past 9 months. I
don't think this is a driver or profile issue but I could be wrong.

Any Ideas or ways to solve this issue.

Thanks for any help.
Bill Giffen