I have a 2004 Ultra. When the tank is full it runs great. When I get down to half or below it spits and sputters. Thinking filter or fuel pump somehow losing pressure. It is fuel injected? Anyone else have this issue.

Have you tried changing fuel caps? If your old cap is clogged and not venting properly it can inhibit the flow of gas from the tank. Think of it as pouring out a bottle. When you let air in it flows smooth but if you cut air off it glugs to get it empty.