Fuel pressure goes from 55 to zero.

[67ChevyRedneck]

00 Z71, 5.3L w/126K.

A couple weeks ago the truck started to not start on the first hit. It was totally random when it did it, sometimes when it sat for a day or two, sometimes right after I just drove it, ect, but it would also sometimes kick right off in the same scenarios.

I put a fuel pressure gauge on the truck today. With the key on, the pressure gets up to what I'm guessing is around 55psi because by the time I get back around the hood to see the gauge it QUICKLY falls to about 20, I haven't waited for it to go to zero, but it starts falling really slow after around 20. I pushed the release valve on my gauge and repeated this several times.

So, is this a fuel pressure regulator or am I looking at a new pump? Does the regulator maintain pressure or hold it back from the pump (keeping it constant)?

Supposedly, a sign of a bad regulator is gas in the vacuum line. Mine is completely clean/dry.

Also, while running, pressure bounces from 54 to 56.

I just did the fuel pump on my s10, am I in for more fuel pump fun?