It will ping when starved for fuel as you have found out.

You should put in an in-line filter just before the pump. That will block what is going to your fuel pump. The pump will go pretty quickly if it's getting that much crud in it.

Get a see through filter similar to this so you can see how dirty it's getting. Take the time to pre-filter the fuel from drums.

EDIT: There is also a screen in the pump that can clog.