I have a newer model dishwasher and now it does not get grease off of plates. It leaves white splotches where the grease was. I have tried some of the cleaners to no avail.
If your dishwasher isn't getting the job done, it may not be getting enough water. The water-inlet valve, which brings water from your outside source, may be responsible. It is easy to replace. You will find it at the bottom of your machine, under the access panel. If it is defective, you can replace it inexpensively. We recommend the site http://www.repairclinic.com for replacement parts.