Air in the fuel line was what my problem turned out to be...

This is what I did:

I disconnected the fuel line from the tank side of the fuel filter, put a can at the hose end and turn the key on w/o the engine running. You should hear the pump run for a second and see a strong flow of gasoline. Reconnect hose.
Disconnect hose from the filter at the engine side to see flow thru the filter. Should also be strong. Reconnect hose.
Locate the pressure relief valve on the fuel rail (looks like a tire valve). Put a can
near it to catch fuel. Turn key on with engine off. Listen for the pump to prime, turn key off. Press valve and watch for stream of fuel. Should be strong.
If not, repeat until it is. Also, try turning the key on with engine off a few times before pressing the valve. You should see a strong flow of fuel. No problem since.

 

I don't see how that's possible.

The system has a pump, lines, the metal injector manifold tube, then a pressure regulator which vents back to the tank.

The pump runs blindly at the same speed all the time when the engine's running. This would create way too much pressure into a closed rail, but the fuel pressure regulator opens up once it reaches the specified pressure letting most of the pump's volume go straight back into the tank at low throttle settings. At higher throttle settings, more of the fuel will be used by the injectors and it dumps less back to the tank. Major waste of amps used to power the pump but oh well.

Air or bad fuel cannot stay in the system. When you turn the key, the pump runs a couple of sec and flushes a bit of fuel from the tank through the lines and manifold. Even if you ran the tank dry and it's totally air in the system, adding fuel to the tank and turning the key like this several times will push new fuel into the lines and manifold and completely purge the air by pushing it through the regulator outlet back into the tank. Same if you have a car that's been sitting for a year and has bad gas in the lines. You clean out the the tank and add fresh gas, turn the key and the cup or so of bad gas lingering in the lines will get flushed back into the tank while the new gas fills the lines.

If you have air in the manifold, then the fuel pump is sucking up air. The pump will pressurize air too. If this is a two-tank system, the fuel switch may be malfunctioning and drawing air from an empty tank. I have been fooled before where I ran out of gas and checked the Schrader valve on the fuel manifold and saw fuel spray but it turned out to be mostly air and a bit of residual fuel I was looking at. I did not have the experience to recognize it.