I am experiencing a problem with my 2005 390MY diesel. The port gauge and smart craft monitor shows a huge difference in the fuel level compared to the starboard tank. I am assuming both of these gauges use the same sending unit. Last night the starboard tank gauge showed 65 gallons while the port tank gauge showed less than 10 gals. remaining. While I thought that both tanks had approx. 65 gals. left, it makes me a little nervous. After running the boat for 20 minutes the port tank registered 47 gals. I have noticed a difference in levels no matter if the tanks are full or not. Again, my guess is the sender unit. Perhaps others have experienced this problem and can reaffirm my assumption before I replace the sending unit.