Ariston A1535 Margherita

My washing machine seems to have some sort of problem with draining. When I run a normal wash i.e. program 2, it stops when it should be draining. I can get round it by running the draining only. It gets stuck again but I run the draining only again once or twice until it finishes without getting stuck. Then I put it on a rinse program. It takes the conditioner and runs ok until it comes to the draining where it just stops. I run the draining only 2 or 3 times again and then put it on spin only. It then runs to the end without problem. The washing is done but what a complicated process. I have tried fitting a new pump but that didn’t make any difference. Any ideas?