Mike - After I installed the Mach 1. 6s I overtightened one of the lines at the #2 injector. Lucky at least that it was easy to get at. I loosened it about 1/2 turn then snugged it back up until the leak stopped. Whew - I got lucky. I was told the worst thing that you can do is to overtighten then either the line cracks or the seal ring does, either way if this happens you need to get a new line. It's important to make sure the seating surfaces of the line and such stays clean a speck of dirt and you've got a leak. I left mine running when I loosened it up, a bunch of fuel spewed out and then as soon as I snugged it back up "presto" it stopped - like I said I got lucky.
Hope this helps stop the leak.