I find the "whole sending unit" (pump and all the level control goodies, mounted on the top of the fuel tank ... hanging down inside.) to be about as well-priced as the pump replacement. It will include the pressure sensor as well. I would replace the whole thing. On my '99 (near 375K miles) I have had to replace the fuel pump a few times ... more than most, I'm sure. I seem to get about 60k-80k miles off of a pump before it starts acting flaky. One failed outright ... it was bad "out of the box".
Maybe the 2000 is different, but my 1999 does not have a ECM. I have looked just now at the electrical diagram book. My PCM controls the engine and tranny. The PCM ain't cheap, several hundred bucks I would think. ... and it takes a lot of Ford proprietary equipment to install properly. I have never had any issues with my PCM ...its been bullet-proof! I wonder what you have been replacing...?? what is a ECM ?...and why??