Well, after 3000 miles, I started having what I think to be the same issue. I replaced the fuel pump (limited lifetime warranty) from O'Reilly's. Now I'm wondering if the problem might actually be a vacuum leak somewhere, and partially shutting off the petcock. When I rebuilt it, I replaced that piece of vacuum tube. Any suggestions?
Also as an FYI, I edited an image of the fuel pump to show terminals of the E16061 ImportDirect pump.