Did you get this sorted out yet?

 

rented a fuel pressure gauge and got a reading of approximately 52 psi at the port under the hood, but it dropped to 40 within about 10 minutes. Need to test at the pump next but don't seem to have the correct adapter to do it. So trying to figure out what to do next.

 

You haven't replaced the filter, have you? Wondering if its having a hard time feeding through, after the pump.

 

that was the starting point for me, being the cheapest/easiest thing to replace and I always do it on anything I buy anyway, but I believe it was already done by the PO as it's the only thing under there with absolutely no dirt on it. I'm still gonna do it but I sorta doubt that's the cause. I feel like its gonna be the pump or the electrical connection at the pump. Especially since it ran flawlessly for one night.

 

Ok so I finally got around to checking pressure at the fuel filter today. Spiked to 95 psi and 10+ minutes later was at 65 psi. According to the thread posted on here, that is an acceptable range/time table. Therefore the problem exists at the injectors. And since the PO said replaced them, I saw that he neglected to put several of the nuts back on the throttle body and accelerator cables. So I suspect his install/reassembly job is half-*** at best. Going to disassemble the upper intake plenum and inspect his work. I'm thinking he went with boneyard parts or something. Will post results.

 

Decided not to go that far just yet. Instead, I checked the torque on all the plenum bolts/nuts and did find that two were slightly below spec. Checked all connections, nothing seems amiss. Yet the issue persists. So here's where we are now:
Fuel pressure is good at pump.
Fuel pressure reaches about 52 psi at port but falls quickly and steeply.
Codes are P0171, P0174, P0300.
Somewhat difficult to start but idles ok.
Wants to bog down or even stall under acceleration, but if I feather it just right I can get it to rev up.
Can manage to do about 45 on my street.
The most mind boggling thing is how it started up and ran so good for just one night. Then right back like it was the next day. Don't want to start tearing things apart and throwing money at it until I do more research. Having said that, I'm already close to $300 deep with the purchase of the fuel pressure test kit, tag, title, and insurance today.
Given the info above, what would be your next move?

 

Check the timing as you said the distributor was loose. I'd also check the inside of the distributor cap and the button (rotor). Are the spark plugs and wires ok?

 

I did manage to pull the cap off and inspect the inside along with the rotor button. Looks to be in good condition. Wires and plugs seem ok. I think if the timing were off I would have a corresponding code set, and also it would not have run perfectly as it did that one night. Even after several key cycles that night it gave me no issue. Until the next day.

 

I managed to data log a couple of trips in it today. How do I post them for you all to see?