Could it be the fuel pump or a related issue? Here is my recent (likely related) experience with our 1995 850 turbo sedan (200+k miles and 17.5 years in our hands). I drove around for a few errands and everything was fine. I parked our car in our garage for ~ 30 minutes; then I wanted to drive somewhere else. The car would not start. There were no codes and everything else seemed fine. Based on past readings/experience, I suspected the fuel pump relay. I did get a new one, put it in, but the problem remained the same. After I checked whatever I could (my knowledge is rather limited however), I decided to have our car towed to my indy mechanic. I let my mechanic know that my car is coming in tow and I called AAA (as a AAA member). The first AAA truck driver that came checked the battery (which is practically new) and electrical system and everything was fine as I suspected too. That AAA driver called in another AAA tow-truck this time to tow my car to my mechanic's store. (Here it is where it gets interesting and ...funny!) The tow truck driver asked me what are the symptoms and after I explained them to him, I also added that it may be the fuel pump since it is still the original one, although I did not really know what the problem was.

NEXT, he went to the back of our car and he pushed it up and down a bit vigorously (I am almost laughing at this time since this move seemed to be unrelated to the towing). After that, he got underneath the back of the car and he banged the gas tank with his hands a few times. Then he came back up again. I barely kept my laughter when I asked him what was he doing. His response was: "sometimes, a small piece of dirt may temporarily clog the fuel pump". Sure enough, my car started right after that, and there was no need for towing! 300 miles later, it is still doing great! I had never heard of such a 'fix'. My mechanic stated that this may/will happen again, but it is unknown when.

If this experience turns out to be helpful to you, please let us know. Good luck!