Thanks all, I will check the grounds tomorrow. It's raining too hard to lie on the ground right now.

And Cap, I checked this pump before I installed it, and when hooked to a battery it works fine.

 

Which connector is on your vehicle harness for the fuel pump module?

 

I installed the updated one with the new pump.
And I spliced the crap out of the wires just to be sure I had good connections.


I suppose I will end up redoing it now, just to be sure that isn't the problem.

 

All 4 of the connections should be soldered using rosin core solder and heat shrink tubing used to insulate the connection. Anything other than that, you're asking for trouble.

 

OK, you're not going to believe this.
I bought a fuel pump, (not the second, the first I bought actually was bad because I tested it outside the truck), and did all this other troubleshooting, and the actual problem was the ground connection that runs up to the drivers side rear corner of the frame.
Apparently what happened was that the bolt on that ground connection vibrated out while I was driving, leaving the wire just sitting on top of the frame. Had I not been hand over handing every wire bundle I saw back there I never would have found it.

Thanks for all your help and hopefully others with a similar problem can get some info from this thread.

 

You would have found it when checkng resistance on the black wires at the fuel pump module! (see post #8)

Good job, glad you found it!