MY 3800 doesn't has an OBDII connector not ALDL so I use another approach when draining the tank.
Disconnect fuel line at the fuel filter. Clamp a 4' length of fuel line to the nipple on the filter. Put end of hose in a 5 gallon gasoline can. Disconnect fuel pump connector at firewall (Yellow connector) Bring connector down below the car ( make sure that its lifted) Make up two wires with male connector pins on the end. Plug one into the gray wire and one into the black wire position. Apply +12 V battery or battery charger power to the wire that goes to the gray lead pin and ground to the black wire pin. That will power up the fuel pump. For stock or 3.4L Fieros Pin G is the better way.
------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "