Gas line/gas mileage problem

I have two problems that I don't think are related but perhaps I am wrong. The first happens when I try to pump/refuel, it keeps clicking off as if the tank were full (I could be on empty and it still does the same thing) it takes forever to fuel up. I thought it was the gas station pump but it happens no matter where I pump my gas. This has been going on for a couple of months.
Second problem, within the last week or two I have been getting horrible gas mileage (20 miles on a 1/4 tank) where as I used to get 85 -90 miles on a 1/4 tank. The engine light is not on. I went through this when I first bought the car and was told it was a sensor.
Would appreciate your thoughts.