My GE profile dishwasher is about 3 years old. There is a sort of white-ish residue on the bottom and on the door running down from the soap dispenser. Is it build up from minerals in the water? Also, it’s not cleaning as well as it used to. I use standard commercial dishwasher soaps. 
What’s the temperature of your hot water at the tap? How long oes it take to reach that temperature?
I am not sure of the temperature. I live in a modern home built in 2000 with one of those systems that circulates hot water through the house…
What you have described sounds like undissolved detergent. Try running a cycle without dishes, with a cup of white vinnegar in the tub.