Fuel pressure numbers are good.
30-40psi is expected.
Although 20psi with key on is low, but you should have also seen a pressure drop with key off after the running test, so not sure where the first 20psi would have come from???
Did you check the Fuel Pressure Regulator's(FPR) vacuum line, I know you removed it for the pressure test, but did you check it for fuel.
A leak in the FPR diaphragm will cause raw fuel to be sucked into the intake, flooding out the engine.
An injector may be stuck open.
You can often use a small hose to listen to each injector while engine is idling, you should get a steady "click, click, click" from each injector, if one sounds "funny" or doesn't "click" then it is stuck.
The ECT(engine coolant temp) sensor is the "choke" for a fuel injected engine, it is a 2 wire sensor used only by the computer.
There is a 1 wire Sender that looks similar but is for the dash board temp gauge.
The ECT tells the computer the engine temp, if cold the computer runs engine rich, raises idle and advances timing(choke mode), as ECT sensor warms up computer leans out the fuel mix, lowers idle and sets regular spark timing.
The computer has a timer that activates when engine is started, if ECT temp is not changing or not changing fast enough you will get code 21, timer is usually set for about 5 minutes, if you get the CEL before that ECT or the wires could be bad.
They are easy to test with OHM meter.
Good site here for Ford sensors:
http://oldfuelinjection.com/?p=28