I have a 12 yr old Frigidaire dishwasher in my manufactured home that won't wash. I run it with plenty of detergent, I have tried pre-rinsing the dishes, I have tried leaving them as-is, I have tried running a light load and I have cleaned out the food residue on the bottom, more than once. I can't afford a new machine yet. How can I get it to work right?!?