I have had similar problems with my 2001 2dr Blazer. It turned out to be hack wiring repairs by the dealership when I had it in for warranty service. so if the new pump for the 2 dr model doesnt work (4dr model didnt work cause its 2 totally dif tank styles) check the wiring. there were prior wiring issues by the transmission cross member and the mech who probed the wires never coated them and they corroded. After paying two mechs I still had to fix it myself. but now the new pump (yeah I replaced the pump b4 i checked to see if it had voltage like a jerk) i got from 1aauto.com now has a faulty pressure sending unit. ac delco is always the way to go trust me its a lesson i learned the hard way from bosch spark plug problems to fuel pumps. theres no reason to keep using parts that are not what chevy uses for a reason