Main harness has been replaced. I can read the codes but at the moment I can't find my file with the code descriptions.

I'm pretty sure the problem is fuel related, as every time I open the fuel system, either changing a pump and/or filter, the pumps startup quiet. I should also make clear that even when the pumps are making noise, the engine runs perfect. The engine died WHEN the pumps were making so much noise that I assume the filter was very clogged and the pumps shutdown.

What's the best way to drain the tank? It appears that there is a debris screen in the bottom of the tank that is replaceable. Should I try that?

Is there any way that the fuel pressure regulator could be malfunctioning? That is, in such a way that even though the engine is getting enough fuel, it's not flowing enough fuel back to the tank to cause the pumps to have to work against the FPR? Just taking a WAG here.

Is there anything else besides the filter than can trap debris and/or obstruct flow to the engine?