PROBLEM SOLVED! Last night I installed the Boyd Plate and while investigating found the problem. While there was some rust and junk that I commonly found in the fuel filters I changed, this piece of plastic was lodged in the inlet/tank outlet. Judging by the diameter, and how carefully I drilled the main hole, this looks like the excrements of the original hole drilled for the tank outlet port. With this in the port it’s been sucking hard for fuel, then some rust and debris sloshes and plugs up what’s left of the port, this caused the chug a chug…die. That little tail on the debris would randomly flap closed and choke off as well.
A reverse blow of the line might had dislodged it, but it’s plastic so would have floated to the inlet eventually.
Take Away:
Don’t waste time removing the tank, use the Boyd plate and you’ll truly fix the problem, and have an easy fix in the future if you don’t install the coffee filter and get debris in the tank again.