Soap suds are left in the bottom of the dishwasher

Dishwasher Repair
1

For some time the dishes have not been getting clean. Several times and inch or two of water has been left standing in the bottom. I will run the dishwasher again and most of the time it will empty but at least one out of five times it will not. I have checked the float, taken the motor and pump off and found nothing abnormal. I have cleaned the drain pipe and found food build up near the disposal but it was still mostly open. Even after all of this, we sometimes have water left standing in the bottom, and when the water is gone the bottom still has soap suds standing over a large area. I have noticed a place on the heating element that looks the two layers have melted through in one spot. When I took the pump off I cleaned the grinder and exit filter. I have not cleaned an intake filter if there is one filtering the city water.

Any suggestions.

2

Have you checked the drain hose installation.
It should be at least a foot higher than where is enters the house plumbing.
If you have an air gap I would check/clean that.

Could be the unit is siphoning dirty water back out of the drain.

I would also check/clean the u trap in the house plumbing drain.