It turns out that the Grand Marquis's antitheft system thought that I was trying to steal the car and had disabled the fuel pump. I read that an ECU from the police version of the Crown Vic can be swapped in, just plug and play, and doesn't take the anti theft into account. Grabbed one from a junkyard cop car, threw it in and the car fired right up and runs smoothly. Booya.
The check engine light is on and I think I need a new scanner, but for now I'm very happy.
While testing the spark plugs, one of the rubber boots ripped off right on the plug at the very bottom of the plug well. What a fuckin 4 hour nightmare that was. I ended up cutting a metal garden stake to become a scraping tool and had to chop at the rubber, blow it out with a compressor, repeat over and over. Ugh.