Just for grins, unhook your fuel line at the fuel pump and blow some air back through the line. If the sock is plugged this will help clean it out. See if it runs any better. If it does and the problem returns, it's time to clean the tank.
One of my Dad's old cars did this when I was a young pup and he carried a tire pump in the car. When it acted up he would blow the line out and it would run fine for quite a while then start acting up again. He did that for a week or two until he could get the car in and get the tank cleaned.
