Fuel pump

Specifications: Maximum 36 - 50 psi Controlled at idle 20 - 24 psi

http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?fromSearchPage=true&pageId=0900c15280066fcb&partName=Fuel+Pressure+Regulator&partId=0900c15280066fcb

What else could the problem be then? If nit the fuel pump,, could it be crank and camshaft position sensors?

You may have leaking injectors

Leaky injector? This isn't a medical self-help site, joemom.... Christian's right re the sensors, but if they're ok AND whacking the starter solves the problem you have worn-out starter solenoid contacts. They're these nice cheap (c. $15) brass pieces that you can swap in yourself in less than an hour if you're handy, but you'll have to lift the beast to get at the starter's lower mounting bolt. Once removed swapping the contacts is duck soup. Sometimes one can simply clean the old contacts, but if they're gouged down it's better to swap in the new jewels. Pretty common with older Subies. RSVP after you push this a bit further.

BTW, it's most probably NOT your fuel pump, as these tend to be go-nogo assemblies; and if one gets intermittent it'd do so while driving (causing stalling) too...which is not your stated problem.