Pulled all the plugs tonight, all were dry, just a tint of white, no shoot or oil, gaps were all correct. They are Iridiums, so I sprayed them off with some high pressure cleaner, checked gap and put them back in.
Again, car fired right up when I cranked it afterwards...so It's going to get driven some this week, then maybe next week change the fuel filter and throw on a new coil...but I can see a new pump coming anyway since the pressure drops so quick...but at least I'll have another driver by then, so no hurry.

 

Good deal Rob..sounds like you have a plan..

 

had a similar problem a while back and it turned out to be a ruptured fuel pressure regulator. Pull the vacuum line off of it and if you find fuel its definitely bad. Happened to my LT1 and a buddy's 3800.

 

That would be a good reason for the pressure drop after turning key off. But it looks like mine is dry after running it for a bit and cycling the key on/off its dry.

 

Finally found the time to drop the tank.
Bench tested the pump assembly out of the tank and found the plastic coil supply line has a crack in it spewing fuel out of it pretty good.
Also found the return line was about to blow off the hose.

Now, the pump seems to be fine, nothing running back through when pump shuts off, nothing running out of the return line either once pump shuts off.

The problem now is, the pump nipple has no dimple in it to connect a regular fuel line to it with a clamp, looks like it much be the crimp kind with teeth only.
Also, I did order a pump assembly, and the pump does not have the o-ring fitting on the pickup end for it to fit snuggly into the carrier box, it does not have the quick disconnect end on the supply side to easily connect to the metal supply tube, and the electrical connect is wrong and too short!!!
It was not for a vendor here, was from my trusty turbo Buick vendor that also sells LT1 parts...not to mention its a 307 pump instead of a 340.

 

Napa = OEM. Try them.

 

Throttle position sensor

 

No, found problem as stated above