[ford38v8]

These problems many times are heat related. The times that it ran poorly and quit on you, then later, started and ran fine, may be more than coincidence. Electrical components develop higher resistance when they get hot, fuel pump valves can operate sluggishly, the flex line softens and collapses, the condenser connection to ground can loosen, the ignition switch can offer high resistance, as will dirty connections, and even the wiring itself will produce more resistance when hot.


Run some tests before you start it in the morning, and compare to identical tests when it runs poorly. While it's hot, you should be able to quickly determine if it is either fuel or electrical, so you can concentrate on one system only. You might even perform these tests a third time after it cools off again, but remember, doing any replacements or adjustments in the interim can muddy the waters on what the cause is/was.


Metal flakes from a new tank sounds fishy. Your fuel filter may be plugged, even though it may look to have just a few flakes in it. You may pull the bottom plug in the tank, to drain and flush into a clean container through a paint filter. Debris found here may be from the tank, or may have been in the fuel put into the tank.


If the filter is under the hood, it may be the fuel line that you don't want to tackle. Even if it's near the tank, the manipulation of the fuel line to disconnect and reconnect to the new tank can disturb the fuel line internally, producing flakes of rust or surface oxidation.


There is a saying, that a problem is likely related to the last thing that was done, but as you've had multiple problems and made so many corrections, the best that can be done to diagnose going forward is to limit future corrections to one system at a time.


The best of luck to you to actually find the problem rather than to correct it with never knowing what you did!