Okay, new o2, new injectors, new CTS. It goes into closed loop finally. I took it for a short drive to warm it up, kept it running in park while I jumped the pins :

Open loop for about 10 seconds and when I revved it up it went into closed loop while holding it at 2k. Let it idle again and it switched between closed and open loop every 2-3 seconds. The engine sounded a tad smoother in open loop while at idle (6-700rpm range)

Couple times SES stayed on or off a few seconds while going to closed loop.
1-15k stayed in closed loop for the most part.

Is all that normal?

Now the fuel pressure issue. I'm 99% sure it's all going through the return line. I can pinch it off and it stops losing pressure.

At idle it holds steady at 31-32lbs. From what I read (or haven't read) I guess that's where it should be?

As to why I'm losing pressure, If the regulator spring was weak, I would think the pressure would only drop so far. Mine drops steadily to 0, like it's just leaking no matter how strong the spring is.

I tried the 3.4 regulator and got the same results. The metal looks smooth, unless there's something I just can't see. I'm thinking monday I might just pick up another fuel rail (or 2, depending on price) at the junkyard.

I've gotten pretty good at changing those things here lately

 

think of the fpr as an intake valve in a head,if it leaks at all it will bleed off all fuel presure.as long as u have proper fp at idle and wot it dosernt matter if the fp is bleeding down once the engine is off.
u know fuel can leak back threw the line from the pump as well if the pump is worn out. but if it bothers u that much place a thing washer ontop of the spring ,and see if it helps at all.
btw u can buy a new fpr diaprham at most auto parts stores for a few bucks