FPR (fuel press. reg.) Question

[johnnymx5]

So im not quite sure how they work or exactly what they do but i have an unknown brand FPR gauge in my car that spikes at above 40 when i turn the ignition to the *on* position and i can hear the fuel pump priming but once the priming sound from the fuel pump stops, the gauge quickly drops to zero. i noticed this while trying to trouble shoot why my car wont start.

do some FPR gauges drop to zero after a few seconds or is something wrong with my fuel pressure? i know the Aeromotive FPR in my RX7 holds its place to only slowwwwlyyyyy taper down over a long period of time with the key still in the on position.

i figured this may be the reason my car isnt starting and was wondering if someone could lead me to a solution instead of getting raped by a towing company and then a mechanic lol thanks