95 GTS - Fuel Pressure bleed down / How quick?

Have you run codes?

Pump could def be bad.

I wouldn't sweat it, same experience as @Mustang5L5. Only thing the fast depressurization can cause is making you have to crank a bit more before the car starts. It does not cause stalling, especially if your fuel pressure is good at idle.

More likely you need to adjust your throttle plate and idle air bleed according to the famous surging idle checklist, and do an ordinary check for vacuum leaks. A hint of missing at idle is normal if your timing is more advanced than your engine likes. Try backing off a degree or two and you'll see it smooth out. A vacuum leak could cause that too.

A stuck-open injector will announce itself with the huge cloud of smoke (white raw fuel vapor) coming out of the tailpipe and horrible driveability. A cylinder balance test can help you eliminate that more easily than unplugging injectors (not so easy when you have to take the upper intake off 8 times).