Sounds like the filter is getting very dirty and lowering the suction needed for the cleaner to run properly. If that is the case, there are two ways to address the problem. 1. Everytime the cleaner stops, clean the filter. 2. Use a manual vac and cut the pipe that comes off the top of the pump and goes to the filter. By eliminating the filter, you should be able to clean the pool a lot faster. You'll have to empty the pump basket often.