Your sludge is coming from your tank. Of that, I have little doubt.
10% ethanol fuel blend has volatile additives in it to make the ethanol perfrm similar to regular unleaded without ethanol.
The unwanted side effect is that this blend is an excellent solvent of the accumulated deposits which normally lie dormant and secure on the sides and bottom of the tank.
This awful blend (which should not be forced upon us in my opinion) moves this otherwise harmless accumulation down stream, causing all kinds of hard to diagnose problems.
It also eats the Carter 2100 YF accelerator pump diaphragms in 1-2 years.
Carl
