We had warnings and electrical issues from the start on this project, replaced battery and all warnings and lights went away. We start it up OK, it runs for 3-5 minutes (depending on idle or under load) then sputters and dies. It will not restart for 15-20 minutes. Checked for plugged CAT, no problem there. No major issues we can speak of and when running, the engine purrs right along. Exhaust seems a little weak coming out the tail (that's why we suspected CAT initially), but with O2 removed in front of CAT to remove pressure, it still stalled out in 5 minutes at an idle.
Any Ideas? Thinking sensor or fuel at this point.