We live in a 70 year old house in the country. The kitchen sink often runs slow, especially after a rain. I have tried drain opener, plunging and running a hose down the pipe. The only thing that works is spraying the hose down the drain when the sink is full. When I do that it will drain, but gets stopped up again.

I also hear a gulping noise from the drain sometimes. Any ideas about making it drain consistently?

Are you on a septic tank??