When you fill the tank do you stop when the pump clicks off or do you try to squeeze more in to round it off to an even dollar amount? If you do that it can cause the fuel light to blink. Over filling it can cause fuel to get in the evaporative emissions system. I found this out when I first bought my car. If I squeezed in a little more after the pump first stopped. The light would come on after it got to about a 1/2 tank. It hasn't blinked sense I stopped trying to squeeze a little more in.