'98 Blazer won't hold fuel pressure - junk gauge?
 

I've read tons of posts on here and am thinking fuel pump but before I go that route, I would like some clarification. Before I get hammered with "did you do the Swartlkk fuel system shuffle" I did and have those numbers. The problem is, I'm questioning whether I trust my gauge. First off, the truck only has 120k on it and was running fine up until a month ago when it seemed to take me cranking it for a second longer than I needed to followed by letting off and then cranking it again to get it started. Then last Monday, it just plain would not start for like three minutes of intermittent cranking. Now this seems to be the norm. I try all sorts of on/off jerking around trying to charge the fuel pump and it seems like that is hit and miss whether or not it helps getting it going. Once going it seems to run fine. I went ahead and sprung for the high dollar harbor freight trash fuel pressure gauge and hooked that up. When I charge the pump it only reads like 50-52 psi. When running it also only reads in that same range. The problem is, as soon as the fuel pump stops running, the pressure drops down to 10 psi in a matter of 10 to 15 seconds. I then hooked the gauge to my '97 full size and it reads 60 psi when the fuel pump charges and while the truck is running it reads around 55 psi but also drops like a rock down to around 10 psi when I shut it off. My 2500 never has had any issues with starting/running so I'm not sure what to think now. Is my gauge a pile or what? So here are my questions then.

Is my gauge to blame for not holding pressure? - I only question this because it drops right up to where the fuel pump check valve is supposed to kick in and then holds at 10 psi. A rather strange coincidence if I didn't indeed have some form of leak. The gauge is not leaking fuel anywhere that I can see.

Is a fuel pump the only cause of me getting 50-52 psi?

I have another fuel pressure regulator from my other motor that I can try, should I or is that a waste of time? (I may do this while I'm waiting for replies so I'll update any changes if/when I get that done) I've already changed the fuel filter which did not help. I noticed that the pump may have gained a little on it's initial charge (52-55 now?) but running pressure is still the same.

Thanks guys