1998 GMC Suburban fuel delivery and or pressure

I just installed my 3rd fuel pump into my 1998 gmc 4x4 suburban, with an automatic trans, and a 5.7L 350 cu. In. Engine. Also I noticed that the fuel filler neck had a rusted pinhole in it so I replaced it. My check engine light went off when I was don (it had been on). My question is what is the proper fuel pressure for this motor, and could my problem possibly be caused by a bad pressure regulator and if so where is it located and what is the procedure for replacing it?